Practice MCQ Questions for Class 12 Chemistry Polymers

MCQ Questions for Class 12 Chemistry Chapter 15 Polymers

Q.1. Orlon is a polymer of:
(a) Styrene
(b) Tetrafluoroethylene
(c) Vinyl chloride
(d) Acrylonitrile

Answer

Answer: (d)


Q.2. Chemically rayon is
(a) Cellulose nitrate
(b) Cellulose sulphate
(c) Cellulose acetate
(d) Cellulose phosphate

Answer

Answer: (c)


Q.3. Which of the following is not a semisynthetic polymer?
(a) cis-polyisoprene
(b) Cellulose nitrate
(c) Cellulose acetate
(d) Vulcanised rubber

Answer

Answer: (a)


Q.4. Nylon-6 is made from
(a) 1, 3-Butadiene
(b) chloroprene
(c) adipic acid
(d) caprolactam

Answer

Answer: (d)


Q.5. Which of the following polymers of glucose is stored by animals? [NCERT Exemplar]
(a) Cellulose
(b) Amylose
(c) Amylopectin
(d) Glycogen

Answer

Answer: (d)


Q.6. Which of the following statements is not true about low density polythene?
(a) Tough
(b) Hard
(c) Poor conductor of electricity
(d) Highly branched structure

Answer

Answer: (d)


Q.7. Which of the following describes a chain terminating step in addition polymerisation?
(a) Reaction of two radicals
(b)Formation of phenyl radical
(c) Addition of radical to ethane
(d) Formation of bigger radicals.

Answer

Answer: (a)


Q.8. The commercial name of polyacrylonitrile is _________________.
(a) Dacron
(b) Orlon (acrilan)
(c) PVC
(d) Bakelite

Answer

Answer: (b)


Q.9. Which of the following is not an example of natural polymer?
(a) Wool
(b) Silk
(c) Leather
(d) Nylon

Answer

Answer: (d)


Q.10. Nylon is an example of
(a) Polyamide
(b) Polyester
(c) Polyethene
(d) Polysaccharide

Answer

Answer: (a)


Q.11. Soft drinks and baby feeding bottles are generally made up of:
(a) Polyester
(b) Polyurethane
(c) Polyurea
(d) Polystyrene

Answer

Answer: (d)


Q.12. Which of the following statement is not correct?
(a) Terylene is polyester polymer
(b) Caprolactum is the monomer of nylon-6
(c) Phenol formaldehyde resin is known as bakelite
(d) The monomer of natural rubber is butadiene

Answer

Answer: (d)


Q.13. Which of the following is a thermosetting plastic?
(a) PVC
(b) PVA
(c) Bakelite
(d) Perspex

Answer

Answer: (c)


Q.14. Which of the following are characteristics of thermosetting polymers? [NCERT Exemplar]
(a) Heavily branched cross linked polymers.
(b) Linear slightly branched long chain molecules.
(c) Become infusible on moulding so cannot be reused.
(d) Soften on heating and harden on cooling, can be reused.

Answer

Answer: (a, c)


Q.15. Novolac on heating with formaldehyde forms
(a) Melamine
(b) Buna-N
(c) Buna-S
(d) Bakelite

Answer

Answer: (d)


Q.16. Which of the following polymers, need atleast one diene monomer for their preparation?
(a) Dacron
(b) Buna-S
(c) Neoprene
(d) Novolac

Answer

Answer: (b, c)


Q.17. Heating of rubber with sulphur is known as:
(a) galvanisation
(b) bessemerisation
(c) vulcanisation
(d) sulphonation

Answer

Answer: (c)


Q.18. Biodegradable polymer which can be produced from glycine and aminocaproic acid is
(a) PHBV
(b) buna-N
(c) nylon2-nylon6
(d) nylon6, 6

Answer

Answer: (c)


Q.19. Natural rubber is a polymer of:
(a) Styrene
(b) Styrene and 1, 3 butadiene
(c) Tetrafluoroethylene
(d) 2-methyl 1, 3-butadiene

Answer

Answer: (d)


Q.20. Polymer used in bullet proof glass is:
(a) PMMA
(b) Laxan
(c) Nomex
(d) Kevlar

Answer

Answer: (b)


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Chemistry MCQs for Class 12 with Answers Chapter 11 Alcohols, Phenols and Ethers

Chemistry MCQs for Class 12 with Answers Chapter 11 Alcohols, Phenols and Ethers

Mon, 16 Aug 2021 07: 06: 53 +0000

Chemistry MCQs for Class 12 with Answers Chapter 11 Alcohols, Phenols and Ethers

MCQs Based On Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on chapter 11 Alcohols, Phenols and Ethers will … Continue reading Chemistry MCQs for Class 12 with Answers Chapter 11 Alcohols, Phenols and Ethers

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MCQs Based On Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers

MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on chapter 11 Alcohols, Phenols and Ethers will also help students in understanding the concepts very well.

Q.1. The compound which reacts fastest with Lucas reagent at room temperature is
(a) Butan-1-ol
(b) Butan-2-ol
(c) 2-Methyl propan-1-ol
(d) 2-Methylpropan-2-ol

Answer

Answer: (d)


Q.2. In the reduction
R — CHO + H2 → RCH2OH
the catalyst used is :
(a) Ni
(b) Pd
(c) Pt
(d) Any of these

Answer

Answer: (d) Any one of Ni, Pt or Pd can be used in the reduction of
aldehydes.


Q.3. Acid catalyzed hydration of alkenes except ethene leads to the formation of
(a) primary alcohol
(b) secondary or tertiary alcohol
(c) mixture of primary and secondary alcohols
(d) mixture of secondary and tertiary alcohols

Answer

Answer: (b)


Q.4. Ethyl alcohol can be prepared from Grignard reagent by the reaction of :
(a) HCHO
(b) R2CO
(c) RCN
(d) RCOCl

Answer

Answer: (a)


Q.5. Isopropyl alcohol is obtained by reacting which of the following alkenes with concentrated H2SO4 followed by boiling with H2O?
(a) Ethylene
(b) Propylene
(c) 2-Methylpropene
(d) Isoprene

Answer

Answer: (b)


Q.6. Ethylene reacts with Baeyer’s reagent to give
(a) ethane
(b) ethyl alcohol
(c) ethylene glycol
(d) None of these

Answer

Answer: (c)


Q.7. Ethyl alcohol is industrially prepared from ethylene by
(a) Permanganate oxidation
(b) Catalytic reduction
(c) Absorbing in H2SO4 followed by hydrolysis
(d) All the three

Answer

Answer: (c)


Q.8. Sodium salt of benzene sulphonic acid on fusion with caustic soda gives
(a) Benzene
(b) Phenol
(c) Thiophenol
(d) Benzoic acid

Answer

Answer: (b)


Q.9. Alkenes convert into alcohols by
(a) hydrolysis by dil. H2SO4
(b) hydration of alkene by alkaline KMnO4
(c) hydrolysis by water vapours and conc. HNO3
(d) hydration of alkene by aqueous KOH

Answer

Answer: (b)


Q.10. Which of the following reacts with NaOH to give an alcohol?
(a) Propene
(b) Butene
(c) Ethanal
(d) Methanal

Answer

Answer: (d)


Q.11. By which of the following methods alcohol can be prepared in excellent yield?
(a) From alkenes
(b) By hydroboration-oxidation
(c) From carbonyl compounds
(d) From Grignard reagent

Answer

Answer: (b)


Q.12. Which of the following compounds is oxidised to prepare methyl ethyl ketone?
(a) 2-Propanol
(b) l-Butanol
(c) 2-Butanol
(d) t-Butyl alcohol

Answer

Answer: (c)


Q.13. HBr reacts fastest with
(a) 2-Mehtylpropan-1-ol
(b) 2-Methylpropene-2-ol
(c) propan-2-ol
(d) propan-1-ol

Answer

Answer: (b) Greater the stability of the intermediate carbocation,
more reactive is the alcohol. Since 2-methylpropan-2-ol
generates 3° carbocation, therefore, it reacts fastest
with HBr.


Q.14. n-Propyl alcohol and isopropyl alcohol can be chemically distinguished by which reagent?
(a) PCl5
(b) Reduction
(c) Oxidation with potassium dichromate
(d) Ozonolysis

Answer

Answer: (c) Primary alcohol on oxidation give aldehyde which on
further oxidation give carboxylic acid whereas
secondary alcohols give ketone.


Q.15. Lucas reagent is
(a) Conc. HCl and anhydrous ZnCl2
(b) Conc. HNO3 and hydrous ZnCl2
(c) Conc. HCl and hydrous ZnCl2
(d) Conc. HNO3 and anhydrous ZnCl2

Answer

Answer: (a)


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Chemistry MCQs for Class 12 with Answers Chapter 10 Haloalkanes and Haloarenes

Chemistry MCQs for Class 12 with Answers Chapter 10 Haloalkanes and Haloarenes

Thu, 12 Aug 2021 07: 44: 04 +0000

Chemistry MCQs for Class 12 with Answers Chapter 10 Haloalkanes and Haloarenes

MCQs Based On Class 12 Chemistry Chapter 10 Haloalkanes and Haloarenes MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on chapter 10 Haloalkanes and Haloarenes will also help … Continue reading Chemistry MCQs for Class 12 with Answers Chapter 10 Haloalkanes and Haloarenes

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MCQs Based On Class 12 Chemistry Chapter 10 Haloalkanes and Haloarenes

MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on chapter 10 Haloalkanes and Haloarenes will also help students in understanding the concepts very well.

Q.1. Gem-dibromide is
(a) CH3CH(Br)CH2(Br)
(b) CH3CBr2CH3
(c) CH2(Br)CH2CH2
(d) CH2BrCH2Br

Answer

Ans. (b) Gem-dihalides are those in which two halogen atoms
are attached on the same carbon atom.


Q.2. IUPAC name of (CH3)3CCl
(a) 3-Chlorobutane
(b) 2-Chloro-2-methylpropane
(c) t-butyl chloride
(d) n-butyl chloride

Answer

Ans. (b)


Q.3. Which of the following is a primary halide?
(a) Isopropyl iodide
(b) Secondary butyl iodide
(c) Tertiary butyl bromide
(d) Neohexyl chloride

Answer

Ans. (d)


Q.4. When two halogen atoms are attached to same carbon atom then it is :
(a) vic-dihalide
(b) gem-dihalide
(c) α, ω -halide
(d) α, β -halide

Answer

Ans. (b)


Q.5. How many structural isomers are possible for a compound with molecular formula C3H7Cl ?
(a) 2
(b) 5
(c) 7
(d) 9

Answer

Ans. (a)


Q.6. The compound which contains all the four 1°, 2°, 3° and 4° carbon atoms is
(a) 2, 3-dimethyl pentane
(b) 3-chloro-2, 3-dimethylpentane
(c) 2, 3, 4-trimethylpentane
(d) 3, 3-dimethylpentane

Answer

Ans. (b)


Q.7. IUPAC name of CH3CH2C(Br) = CH—Cl is
(a) 2-bromo-1-chloro butene
(b) 1-chloro-2-bromo butene
(c) 3-chloro-2-bromo butene
(d) None of the above

Answer

Ans. (a)


Q.8. Benzene hexachloride is
(a) 1, 2, 3, 4, 5, 6 – hexachlorocyclohexane
(b) 1, 1, 1, 6, 6, 6 – hexachlorocyclohexane
(c) 1, 6 – phenyl – 1, 6 – chlorohexane
(d) 1, 1 – phenyl – 6, 6 -chlorohexane

Answer

Ans. (a)


Q.9. The IUPAC name of CH2 = CH—CH2Cl is
(a) Allyl chloride
(b) 1-chloro-3-propene
(c) Vinyl chloride
(d) 3-chloro-1-propene

Answer

Ans. (d)


Q.10. Which of the following halide is 2° ?
(a) Isopropyl chloride
(b) Isobutyl chloride
(c) n-propyl chloride
(d) n-butyl chloride

Answer

Ans. (a)


Q.11. Halogenation of alkanes is
(a) a reductive process
(b) an oxidative process
(c) an isothermal process
(d) an endothermal process

Answer

Ans. (b)


Q.12. C – X bond is strongest in
(a) CH3Cl
(b) CH3Br
(c) CH3F
(d) CH3I

Answer

Ans. (c) Because of the small size of F, the C–F bond is strongest
in CH3F.


Q.13. Which of the following will have the maximum dipole moment?
(a) CH3F
(b) CH3Cl
(c) CH3Br
(d) CH3I

Answer

Ans. (b) CH3Cl has higher dipole moment than CH3F due to
much longer C–Cl bond length than the C–F bond.
The much longer bond length of the C–C bond
outweighs the effect produced by lower
electronegativity of Cl than that of F.


Q.14. Phosgene is a common name for
(a) phosphoryl chloride
(b) thionyl chloride
(c) carbon dioxide and phosphine
(d) carbonyl chloride

Answer

Ans. (d)


Q.15. In the preparation of chlorobenzene from aniline, the most suitable reagent is
(a) Chlorine in the presence of ultraviolet light
(b) Chlorine in the presence of AlCl3
(c) Nitrous acid followed by heating with Cu2Cl2
(d) HCl and Cu2Cl2

Answer

Ans. (c)


Q.16. Ethylene dichloride can be prepared by adding HCl to
(a) Ethane
(b) Ethylene
(c) Acetylene
(d) Ethylene glycol

Answer

Ans. (d)


Q.17. In which of the following conversions, phosphorus pentachloride is used as the reagent?
(a) H2C = CH2 CH3CH2Cl
(b) CH3CH2OH CH3CH2Cl
(c) H3C-O-CH3 CH3Cl
(d) CH CH CH2 = CHCl

Answer

Ans. (b)


Q.18. The decreasing order of boiling points of alkyl halides is
(a) RF > RCl > RBr > RI
(b) RBr > RCl > RI > RF
(c) RI > RBr > RCl > RF
(d) RCl > RF > RI > RBr

Answer

Ans. (c) For the same alkyl group, the boiling points of alkyl
halides decrease in the order :

RI > RBr > RCl > RF

This is because with the increase in size and mass of
halogen atom, the magnitude of van der Waal’s forces
increases.


Q.19. The best method for the conversion of an alcohol into an alkyl chloride is by treating the alcohol with
(a) PCl5
(b) dry HCl in the presence of anhydrous ZnCl2
(c) SOCl2 in presence of pyridine
(d) None of these

Answer

Ans. (c)


Q.20. Which of the following is liquid at room temperature (b.p. is shown against it)?
(a) CH3I 42ºC
(b) CH3Br 3ºC
(c) C2H5Cl 12ºC
(d) CH3F –78ºC

Answer

Ans. (a)


Q.21. The catalyst used in the preparation of an alkyl chloride by the action of dry HCl on an alcohol is
(a) anhydrous AlCl3
(b) FeCl3
(c) anhydrous ZnCl2
(d) Cu

Answer

Ans. (c) In preparation of an alkyl chloride by the action of dry
HCl, the catalyst generally used is anhydrous ZnCl2.


Q.22. Chlorobenzene is prepared commercially by
(a) Raschig process
(b) Wurtz Fittig reaction
(c) Friedel-Craft’s reaction
(d) Grignard reaction

Answer

Ans. (a)


Q.23. Conant Finkelstein reaction for the preparation of alkyl iodide is based upon the fact that
(a) Sodium iodide is soluble in methanol, while sodium chloride is insoluble in methanol
(b) Sodium iodide is soluble in methanol, while NaCl and NaBr are insoluble in methanol
(c) Sodium iodide is insoluble in methanol, while NaCl and NaBr are soluble
(d) The three halogens differ considerably in their electronegativity

Answer

Ans. (b)


Q.24. Which of the following possesses highest melting point?
(a) Chlorobenzene
(b) m-dichlorobenzene
(c) o-dichlorobenzene
(d) p-dichlorobenzene

Answer

Ans. (d)


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Chemistry MCQs for Class 12 with Answers Chapter 7 The p-Block Elements

Chemistry MCQs for Class 12 with Answers Chapter 7 The p-Block Elements

Wed, 11 Aug 2021 05: 55: 27 +0000

Chemistry MCQs for Class 12 with Answers Chapter 7 The p-Block Elements

MCQs Based On Class 12 Chemistry Chapter 7 The p-Block Elements MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on chapter 7 The p-Block Elements will also help … Continue reading Chemistry MCQs for Class 12 with Answers Chapter 7 The p-Block Elements

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MCQs Based On Class 12 Chemistry Chapter 7 The p-Block Elements

MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on chapter 7 The p-Block Elements will also help students in understanding the concepts very well.

Q.1. Among the 15th group elements, as we move from nitrogen to bismuth, the pentavalency becomes less pronounced and trivalency becomes more pronounced due to
(a) Non metallic character
(b) Inert pair effect
(c) High electronegativity
(d) Large ionization energy

Answer

Ans. (b)


Q.2. Which of the following statements is not correct for nitrogen?
(a) Its electronegativity is very high
(b) d-orbitals are available for bonding
(c) It is a typical non-metal
(d) Its molecular size is small

Answer

Ans. (b) In case of nitrogen, d-orbitals are not available.


Q.3. Collectively the elements of group 15 are called –
(a) pnicogens
(b) pnicopens
(c) nicopen
(d) None of these

Answer

Ans. (a) Collectively these elements are called pnicogens and
their compound pniconides.


Q.4. Ionic radii (in Å) of As3+, Sb3+ and Bi3+ follow the order
(a) As3+ > Sb3+ > Bi3+
(b) Sb3+ > Bi3+ >As3+
(c) Bi3+ > As3+ > Sb3+
(d) Bi3+ > Sb3+ > As3+

Answer

Ans. (d) Ionic radii increases down the group


Q.5. Which one of the following elements is most metallic ?
(a) P
(b) As
(c) Sb
(d) Bi

Answer

Ans. (d) Metallic character increases down the group, Bi is
most metallic


Q.6. Which of the follow group 15 element forms metallic bonds in elemental state ?
(a) As
(b) P
(c) Sb
(d) Bi

Answer

Ans. (d) Bismuth forms metallic bonds in elemental state.


Q.7. The three important oxidation states of phosphorus are
(a) –3, +3 and +5
(b) –3, +3 and –5
(c) –3, +3 and +2
(d) –3, +3 and +4

Answer

Ans. (a) –3, +3, +5


Q.8. Which of the following statement is incorrect for group 15 elements ?
(a) Order of ionization enthalpies is ΔiH1 < ΔiH2 < ΔiH3
(b) The boiling point and melting point increases from top to bottom in the group
(c) Dinitrogen is a gas while all others are solids
(d) All statements are correct

Answer

Ans. (b) The melting point in group 15 increases upto arsenic
and then decreases upto bismuth.


Q.9. Nitrogen is relatively inactive element because
(a) its atom has a stable electronic configuration
(b) it has low atomic radius
(c) its electronegativity is fairly high
(d) dissociation energy of its molecule is fairly high

Answer

Ans. (d) N2 molecule contains triple bond between N atoms
having very high dissociation energy (946 kJ mol–1)
due to which it is relatively inactive.


Q.10. Which of the following has the highest pπ – pπ bonding tendency ?
(a) N
(b) P
(c) As
(d) Sb

Answer

Ans. (a) Nitrogen due to small size is able to show pπ-pπ lateral
overlap forming N≡N, rest elements due to bigger size
are not able to show pπ-pπ lateral overlap.


Q.11. Pick out the wrong statement.
(a) Nitrogen has the ability to form pπ-pπ bonds with itself.
(b) Bismuth forms metallic bonds in elemental state.
(c) Catenation tendency is higher in nitrogen when compared with other elements of the same group.
(d) Nitrogen has higher first ionisation enthalpy when compared with other elements of the same group.

Answer

Ans. (c) Catenation tendency is higher in phosphorus when
compared with other elements of same group.


Q.12. Nitrogen forms N2, but phosphorus is converted into P4 from P, the reason is
(a) Triple bond is present between phosphorus atom
(b) pπ – pπ bonding is strong
(c) pπ – pπ bonding is weak
(d) Multiple bond is formed easily

Answer

Ans. (c)


Q.13. What causes nitrogen to be chemically inert ?
(a) Multiple bond formation in the molecule
(b) Absence of bond polarity
(c) Short internuclear distance
(d) High bond energy

Answer

Ans. (d)


Q.14. Pentavalence in phosphorus is more stable when compared to that of nitrogen even though they belong to same group. This is due to
(a) dissimilar electronic configuration
(b) due to presence of vacant d-orbitals
(c) reactivity of phosphorus
(d) inert nature of nitrogen

Answer

Ans. (b) Phosphorous can achieve coordination number 5 due
to vacant d atomic orbitals in valence shell which is
not possible in nitrogen


Q.15. Which one has the lowest boiling point ?
(a) NH3
(b) PH3
(c) AsH3
(d) SbH3

Answer

Ans. (b)


Nitrogen does not form pentahalide. Why?

Nitrogen can not expand its octet due to absence of d-orbitals.

BiH3 is the strongest reducing agent amongst all the hydrides of group 15. Why?

Among hydrides of group-15 elements, the bond length increases from N – H to Bi – H with increasing size of element. Bi – H bond is longest and weakest, it can break more easily and evolve H2 gas which acts as the reducing agent.

Why is NH3 more basic than PH3?

Lewis basic nature of NH3 and PH3 molecules is due to the presence of lone pairs on N and Bi atoms, respectively. P atom is much larger than N atom and also has empty d orbitals. Electron density due to lone pair on P gets diffused because of the presence of d-orbitals and so the lone pair is not easily available for donation. Hence PH3 is less basic than NH3.

Why is the single N N bond weaker than the single P P bond?

The single N—N bond is weaker than the single P—P bond because of high interelectronic repulsion of the non-bonding electrons, occurring due to the small bond length.

Bi is a strong oxidizing agent in the +5 state.

On moving down the group, the stability of +5 oxidation state decreases while +3 oxidation state
increases due to inert pair effect.
Thus +5 oxidation state of Bi is less stable and Bi(V) is a stronger oxidising agent.

Tendency to form pentahalides decreases down the group in group 15 of the periodic table. Why?

Due to inert pair effect the stability of +5 oxidation state decreases down the group in group 15. Hence tendency to form pentahalide decreases down the group 15 of the periodic table.

Why are pentahalides of a metal more covalent than its trihalides?

In + 5 oxidation state charge/radius ratio is higher than that in + 3 oxidation state. Hence, +5 oxidation state has more polarising power than that of + 3 oxidation state and pentahalides (in O.S. + 5) are more covalent than trihalides.

Ammonia has a higher boiling point than phosphine. Why?

NH3 molecules are held together by strong inter molecular hydrogen bonds whereas PH3 molecules are held together by weak van der Waals bonds. Thus, NH3 has a higher boiling point than PH3.

White phosphorus is more reactive than red phosphorus.

White phosphorus consists of discrete P4 molecules in which each phosphorus atom is tetrahedrally bonded to other three phosphorus atoms. So, white phosphorus is highly reactive. In red phosphorus, P4 molecules are linked in an extended chain structure. So, red phosphorus is much less reactive.

There is large difference between the melting and boiling points of oxygen and sulphur.

Oxygen molecules are held together by weak van der Waals’ forces because of the small size and high electronegativity of oxygen. Sulphur shows catenation and the molecule is made up of 8 atoms with strong intermolecular forces.
Hence, there is large dierence in the melting and boiling points of oxygen and sulphur.

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Chemistry MCQs for Class 12 with Answers Chapter 2 Solutions

Chemistry MCQs for Class 12 with Answers Chapter 2 Solutions

Sat, 17 Jul 2021 16: 51: 01 +0000

Chemistry MCQs for Class 12 with Answers Chapter 2 Solutions

MCQs Based On Class 12 Chemistry Chapter 2 Solutions MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on Chapter 2 Solutions will also help students in understanding the concepts … Continue reading Chemistry MCQs for Class 12 with Answers Chapter 2 Solutions

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MCQs Based On Class 12 Chemistry Chapter 2 Solutions

MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on Chapter 2 Solutions will also help students in understanding the concepts very well.

Q.1. Which of the following fluoride is used as rat poison?
(a) CaF2
(b) KF
(c) NaF
(d) MgF2

Answer

(c) Sodium fluoride is used as rat poison.


Q.2. Vapour pressure of a pure liquid X is 2 atm at 300 K. It is lowered to 1 atm on dissolving 1 g of Y in 20 g of liquid X. If molar mass of X is 200, what is the molar mass of Y?
(a) 20
(b) 50
(c) 100
(d) 200

Answer

Answer: (b) 50


Q.3. Most of the processes in our body occur in
(a) solid solution
(b) liquid solution
(c) gaseous solution
(d) colloidal solution

Answer

(b) Almost all the processes in our body occur in liquid
solution.


Q.4. The term homogenous mixtures signifies that
(a) its composition is uniform throughout the mixture.
(b) its properties are uniform throughout the mixture.
(c) both composition and properties are uniform
throughout the mixture.
(d) neither composition nor properties are uniform
throughout the mixture.

Answer

(c) In homogeneous mixtures composition and properties
both are uniform throughout the mixture.


Q.5. Which of the following units is useful in relating concentration of solution with its vapour pressure?
(a) Mole fraction
(b) Parts per million
(c) Mass percentage
(d) Molality

Answer

(a) Mole fraction


Q.6. Which of the following mixture is(are) called solution?
(i) water + ammonia (ii) water + acetone
(iii) acetone + alcohol (iv) hexane + water
(a) (i), (ii) and (iii) (b) (i), (iii) and (iv)
(c) (i) and (iv) (d) (ii) and (iii)

Answer

(a) Hexane is not water soluble, hence solution is not
formed.


Q.7. A plant cell shrinks when it is kept in a
(a) hypotonic solution
(b) hypertonic solution
(c) isotonic solution
(d) pure waterAnswer

Answer

(b) hypertonic solution



Q.8. The relative lowering in vapour pressure is proportional to the ratio of number of
(a) solute molecules to solvent molecules
(b) solvent molecules to solute molecules
(c) solute molecules to the total number of molecules in solution
(d) solvent molecules to the total number of molecules in solutionAnswer

Answer

(c) solute molecules to the total number of molecules in solution


Q.9. Which of the following is a quantitative description of the solution?
(a) Dilute
(b) Concentrated
(c) Saturated
(d) Molar

Answer

(d) Dilute, concentrated and saturated terms are
qualitative methods of description of concentration
of solution whereas molar or molarity is quantitative
method.


Q.10. When a solute is present in trace quantities the following expression is used
(a) Gram per million
(b) Milligram percent
(c) Microgram percent
(d) Parts per million

Answer

(d)


Q.11. The law which indicates the relation’-hip between solubility of a gas in liquid and pressure rs
(a) Raoult’s law
(b) Henry’s law
(c) Lowering of vapour pressure
(d) Van’t Hoff lawAnswer

Answer

Answer: (b) Henry’s law


Q.12. Molarity of liquid HCl will be, if density of solution is 1.17 gm/cc
(a) 36.5
(b) 32.05
(c) 18.25
(d) 42.10

Answer

(b)


Q.13. 1 M, 2.5 litre NaOH solution is mixed with another 0.5 M, 3 litre NaOH solution. Then find out the molarity of resultant solution
(a) 0.80 M
(b) 1.0 M
(c) 0.73 M
(d) 0.50 M

Answer

(c)


Q.14. How much oxygen is dissolved in 100 rnL water at 298 K if partial pressure of oxygen is 0.5 atm and K = 1.4 × 10-3 mol/L/atm?
(a) 22.4 mg
(b) 22.4 g
(c) 2.24 g
(d) 2.24 mg

Answer

Answer: (d) 2.24 mg


Q.15. An X molal solution of a compound in benzene has mole fraction of solute equal to 0.2. The value of X is
(a) 14
(b) 3.2
(c) 1.4
(d) 2

Answer

(b)


Q.16. The molarity of the solution containing 7.1 g of Na2SO4 in 100 ml of aqueous solution is
(a) 2 M
(b) 0.5 M
(c) 1 M
(d) 0.05 M

Answer

(b)


Q.17. Partial pressure of a solution component is directly proportional to its mole fraction. This is known as
(a) Henry’s law
(b) Raoult’s law
(c) Distribution law
(d) Ostawald’s dilution law

Answer

Answer: (b) Raoult’s law


Q.18. 3 moles of P and 2 moles of Q are mixed, what will be their total vapour pressure in the solution if their partial vapour pressures are 80 and 60 torr respectively?
(a) 80 torr
(b) 140 torr
(c) 72 torr
(d) 70 torr

Answer

Answer: (c) 72 torr


Q.19. Sprinkling of salt helps in clearing the snow covered roads in hills. The phenomenon involved in the process is
(a) lowering in vapour pressure of snow
(b) depression in freezing point of snow
(c) melting of ice due to increase in temperature by putting salt
(d) increase in freezing point of snow

Answer

Answer: (b) depression in freezing point of snow


Q.20. Which of the following solutions shows positive deviation from Raoult’s law?
(a) Acetone + Aniline
(b) Acetone + Ethanol
(c) Water + Nitric acid
(d) Chloroform + Benzene

Answer

Answer: (b) Acetone + Ethanol


Q.21. The system that forms maximum boiling azetrope is
(a) Acetone-chloroform
(b) ethanol-acetone
(c) n-hexane-n-heptane
(d) carbon disulphide-acetone

Answer

Answer: (a) Acetone-chloroform



Q.22. A solution containing 10.2 g glycerine per litre is isotonic with a 2% solution of glucose. What is the molecular mass of glycerine?
(a) 91.8 g
(b) 1198 g
(c) 83.9 g
(d) 890.3 g

Answer

Answer: (a) Acetone-chloroform


Q.23. What weight of glycerol should be added to 600 g of water in order to lower its freezing point by 10°C ?
(a) 496 g
(b) 297 g
(c) 310 g
(d) 426 g

Answer

Answer: (b) 297 g


Q.24. The osmotic pressure of a solution can be increased by
(a) increasing the volume
(b) increasing the number of solute molecules
(c) decreasing the temperature
(d) removing semipermeable membrane

Answer

Answer: (b) increasing the number of solute molecules



Q.25. For carrying reverse osmosis for desalination of water the material used for making semipermeable membrane is
(a) potassium nitrate
(b) parchment membrane
(c) cellulose acetate
(d) cell membrane

Answer

Answer: (c) cellulose acetate


Q.26. What will be the degree of dissociation of 0.1 M Mg(NO3)2 solution if van’t Hoff factor is 2.74?
(a) 75%
(b) 87%
(c) 100%
(d) 92%

Answer

Answer: (b) 87%



Q.27. At equilibrium the rate of dissociation of a solid solute in a volatile liquid solvent is
(a) less than the rate of crystallisation
(b) greater than the rate of crystallisation
(c) equal to the rate of crystallisation
(d) zero

Answer

Answer: (c) equal to the rate of crystallisation


Q.28. If 2 gm of NaOH is present is 200 ml of its solution, its molarity will be
(a) 0.25
(b) 0.5
(c) 5
(d) 10

Answer

Answer: (a) 0.25


Q.29. The atmospheric pollution is generally measured in the units of
(a) mass percentage
(b) volume percentage
(c) volume fraction
(d) ppm

Answer

Answer: (d) ppm


Q.30. A 5% solution of cane-sugar (molecular weight = 342) is isotonic with 1% solution of substance A. The molecular weight of X is
(a) 342
(b) 171.2
(c) 68.4
(d) 136.8

Answer

Answer: (c) 68.4


Q.31. 234.2 gm of sugar syrup contains 34.2 gm of sugar. What is the molal concentration of the solution.
(a) 0.1
(b) 0.5
(c) 5.5
(d) 55

Answer

Answer: (b) 0.5


Q.32. H2S is a toxic gas used in qualitative analysis. If solubility of H2S in water at STP is 0.195 m. what is the value of KH?
(a) 0.0263 bar
(b) 69.16 bar
(c) 192 bar
(d) 282 bar

Answer

Answer: (d) 282 bar


Q.33. Atomic mass is equal to
(a) number of electrons of an atom
(b) sum of the numbers of electrons and protons of an atom
(c) sum of the numbers of neutrons and protons of an atom
(d) none of these

Answer

Answer: (b) sum of the numbers of electrons and protons of an atom


Q.34. Henry’s law constant for molality of methane is benzene at 298 K is 4.27 × 105 mm Hg. The mole fraction of methane in benzene at 298 K under 760 mm Hg is
(a) 1.78 × 10-3
(b) 17.43
(c) 0.114
(d) 2.814

Answer

Answer: (a)



Q.35. Among the following substances the lowest vapour pressure is exerted by
(a) water
(b) alcohol
(c) ether
(d) mercury

Answer

Answer: (d) mercury


Q36. At equillibrium the rate of dissolution of a solid solute in a
volatile liquid solvent is __.
(a) less than the rate of crystallisation.
(b) greater than the rate of crystallisation.
(c) equal to the rate of crystallisation.
(d) zero

Answer

Answer: (c)


Q.37. A beaker contains a solution of substance ‘A’. Precipitation of substance ‘A’ takes place when small amount of ‘A’ is added to the solution. The solution is __.
(a) saturated
(b) supersaturated
(c) unsaturated
(d) concentrated

Answer

Answer: (b) If added substance dissolves, the solution is
unsaturated. If it does not dissolve solution is
saturated. If precipitation occurs solution is
supersaturated.


Q.38. Maximum amount of a solid solute that can be dissolved in a specified amount of a given liquid solvent does not depend upon ________.
(a) Temperature
(b) Nature of solute
(c) Pressure
(d) Nature of solvent

Answer

Answer: (c)


Q.39. Low concentration of oxygen in the blood and tissues of people living at high altitude is due to _.
(a) low temperature
(b) low atmospheric pressure
(c) high atmospheric pressure
(d) both low temperature and high atmospheric pressure

Answer

Answer: (b) Body temperature of human beings remains constant.


Q.40. Value of Henry’s constant KH _.
(a) increases with increase in temperature.
(b) decreases with increase in temperature.
(c) remains constant.
(d) first increases then decreases.

Answer

Answer: (a)


Q.41. The value of Henry’s constant KH is _.
(a) greater for gases with higher solubility.
(b) greater for gases with lower solubility.
(c) constant for all gases.
(d) not related to the solubility of gases.

Answer

Answer: (b)


Frequently Asked Questions – FAQs

What is Solution?

A perfectly homogeneous mixture of two or more components is called solution.

What is Solute?

The component which is present in lesser amount or whose physical state is changed during the formation of solution is called solute.

What is a Solvent?

The component which is present in larger amount and determines the physical state of the solution is called solvent.

How many types of solutions are there?

Depending upon the nature of solute and solvent, solutions are classified as follows : (a) Gaseous solutions (b) Liquid solutions (c) Solid solutions

What is solubility?

Maximum amount of substance that can be dissolved in a specified amount of solvent at a specified temperature is called its solubility.

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15104

Chemistry MCQs for Class 12 with Answers Chapter 1 Solid State

Chemistry MCQs for Class 12 with Answers Chapter 1 Solid State

Sat, 17 Jul 2021 10: 10: 45 +0000

Chemistry MCQs for Class 12 with Answers Chapter 1 Solid State

MCQ Questions Based On Class 12 Chemistry Term 1 Syllabus MCQ Questions for Class 12 Chemistry Chapter 2 Solutions MCQ Questions for Class 12 Chemistry Chapter 7 The p-Block Elements MCQ Questions for Class 12 Chemistry Chapter 10 Haloalkanes and Haloarenes MCQ Questions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers MCQ Questions … Continue reading Chemistry MCQs for Class 12 with Answers Chapter 1 Solid State

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Home » CBSE Class 12 Chemistry » MCQ Questions for Class 12 Chemistry

MCQ Questions Based On Class 12 Chemistry Term 1 Syllabus

MCQs based on class 12 chemistry chapter 1 solid state

MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on chapter 1 solid state will also help students in understanding the concepts very well.

Q.1. Which of the following statements about amorphous solids is incorrect ?
(a) They melt over a range of temperature
(b) They are anisotropic
(c) There is no orderly arrangement of particles
(d) They are rigid and incompressible

Answer

Ans. (b) Amorphous solids are isotropic, because these
substances show same properties in all directions.


Q.2. Which of the following statement is not true about amorphous solids ?
(a) On heating they may become crystalline at certain temperature.
(b) They may become crystalline on keeping for long time.
(c) Amorphous solids can be moulded by heating.
(d) They are anisotropic in nature.

Answer

Ans. (d)


Q.3. Which of the following is not a characteristic property of solids?
(a) Intermolecular distances are short.
(b) Intermolecular forces are weak.
(c) Constituent particles have fixed positions.
(d) Solids oscillate about their mean positions.

Answer

Ans. (b) Intermolecular forces are strong in solids.


Q.4. Most crystals show good cleavage because their atoms, ions or molecules are
(a) weakly bonded together
(b) strongly bonded together
(c) spherically symmetrical
(d) arranged in planes

Answer

Ans. (d) Crystals show good cleavage because their constituent
particles are arranged in planes.


Q.5. The coordination number of Y will be in the XY types of crystal:
(a) 6
(b) 8
(c) 12
(d) 4

Answer

Ans. (a) 6


Q.6. Which of the following is not a crystalline solid?
(a) KCl
(b) CsCl
(c) Glass
(d) Rhombic S

Answer

Ans. (c) Glass is amorphous solid.


Q.7. Which of the following is an amorphous solid ?
(a) Graphite (C)
(b) Quartz glass (SiO2)
(c) Chrome alum
(d) Silicon carbide (SiC)

Answer

Ans. (b)


Q.8. “Crystalline solids are anisotropic in nature. What is the meaning of anisotropic in the given statement?
(a) A regular pattern of arrangement of particles which repeats itself periodically over the entire crystal.
(b) Different values of some of physical properties are shown when measured along different directions in
the same crystals.
(c) An irregular arrangement of particles over the entire crystal.
(d) Same values of some of physical properties are shown when measured along different directions in the same crystals.

Answer

Ans. (b) Crystalline solids are anisotropic in nature that is some
of their physical properties like electrical resistance
or refractive index show different values when
measured along different directions in the same
crystals.


Q.9. A crystalline solid
(a) changes abruptly from solid to liquid when heated
(b) has no definite melting point
(c) undergoes deformation of its geometry easily
(d) has an irregular 3-dimensional arrangements

Answer

Ans. (a) In crystalline solid there is perfect arrangement of the
constituent particles only at 0 K. As the temperature
increases the chance that a lattice site may be
unoccupied by an ion increases. As the number of
defects increases with temperature solid changes into
liquid.


Q.10. Which of the following is not a characteristic of a crystalline solid ?
(a) Definite and characteristic heat of fusion.
(b) Isotropic nature.
(c) A regular periodically repeated pattern of arrangement of constituent particles in the entire crystal.
(d) A true solid

Answer

Ans. (b)


Q.11. Which of the following is not a crystalline solid?
(a) KCl
(b) CsCl
(c) Glass
(d) Rhombic S

Answer

Ans. (c) Glass is amorphous solid.


Q.12. Which one of the following is non-crystalline or amorphous?
(a) Diamond
(b) Graphite
(c) Glass
(d) Common Salt

Answer

Ans. (c) Glass



Q.13. In Zinc blende structure
(a) zinc ions occupy half of the tetrahedral sites
(b) each Zn2- ion is surrounded by six sulphide ions
(c) each S2- ion is surrounded by six Zn2+ ions
(d) it has fee structure

Answer

Ans. (c) each S2- ion is surrounded by six Zn2+ ions


Q.14. A unit cell of BaCl2 (fluorite structure) is made up of
(a) four Ba2+ ions and four Cl ions
(b) four Ba2- ions and eight Cl ions
(c) eight Ba² ions and four Cl ions
(d) four Ba² ions and six Cl ions

Answer

Ans. (b) four Ba2- ions and eight Cl ions


Q.15. Alkali halides do not show Frenkel defect because
(a) cations and anions have almost equal size
(b) there is a large difference in size of cations and anions
(c) cations and anions have low coordination number
(d) anions cannot be accommodated in voids

Answer

Ans. (a) cations and anions have almost equal size



Q.16. The fraction of the total volume occupied by the atoms present in a simple cube is
(a) π/4
(b) π/6
(c) π/3√2
(d) π/4√2

Answer

Ans. (b) π/6


Q.17. Edge length of unit cell of chromium metal is 287 pm with bcc arrangement. The atomic radius is of the order
(a) 287 pm
(b) 574 pm
(c) 124.27 pm
(d) 143.5 pmAnswer

Answer

Ans. (c) 124.27 pm


Q.18. The edge length of fee cell is 508 pm. If radius of cation is 110 pm, the radius of anion is
(a) 110 pm
(b) 220 pm
(c) 285 pm
(d) 144 pm

Answer

Ans. (d) 144 pm


Q.19. The density of a metal which crystallises in bcc lattice with unit cell edge length 300 pm and molar mass 50 g mol-1 will be
(a) 10 g cm-3
(b) 14.2 g cm-3
(c) 6.15 g cm-3
(d) 9.3 2 g cm-3

Answer

Ans. (c)


Q.20. p-type semiconductors are formed When Si or Ge are doped with
(a) group 14 elements
(b) group 15 elements
(c) group 13 elements
(d) group 18 elements

Answer

Ans. (c)


Q.21. Which of the following conditions favours the existence of a substance in the solid state?
(a) High temperature
(b) Low temperature
(c) High thermal energy
(d) Weak cohesive forces

Answer

Ans. (b)


Q.22. How many lithium atoms are present in a unit cell with edge length 3.5 Å and density 0.53 g cm-3? (Atomic mass of Li = 6.94):
(a) 2
(b) 1
(c) 4
(d) 6

Answer

Ans. (a)


Q.23. The distance between Na and CL ions in NaCl with a density 2.165 g cm-3 is
(a) 564 pm
(b) 282 pm
(c) 234 pm
(d) 538 pm

Answer

Ans. (b)


Q.24. An element with atomic mass 100 has a bcc structure and edge length 400 pm. The density of element is
(a) 10.37 g cm-3
(b) 5.19 g cm-3
(c) 7.29 g cm-3
(d) 2.14 g cm-3

Answer

Ans. (b)


Q.25. Fe3O4 (magnetite) is an example of
(a) normal spinel structure
(b) inverse spinel structure
(c) fluoride structure
(d) anti fluorite structure

Answer

Ans. (b)


Q.26. Which of the following crystals does not exhibit Frenkel defect?
(a) AgBr
(b) AgCl
(c) KBr
(d) ZnS

Answer

Ans. (c)


Q.27. What type of stoichiometric defect is shown by ZnS?
(a) Schottky defect
(b) Frenkel defect
(c) Both Frenkel and Schottky defects
(d) Non-stoichiometric defect

Answer

Ans. (b)


Q.28. NaCl type crystal (with coordination no. 6 : 6) can be converted into CsCl type crystal (with coordination no. 8 : 8) by applying
(a) high temperature
(b) high pressure
(c) high temperature and high pressure
(d) low temperature and low pressure

Answer

Ans. (b)


Q.29. How many chloride ions are surrounding sodium ion in sodium chloride crystal ?
(a) 4
(b) 8
(c) 6
(d) 12

Answer

Ans. (c)


Q.30. In NaCl structure
(a) all octahedral and tetrahedral sites are occupied
(b) only octahedral sites are occupied
(c) only tetrahedral sites are occupied
(d) neither octahedral nor tetrahedral sites are occupied

Answer

Ans. (b)


Q.31. Silver halides generally show
(a) Schottky defect
(b) Frenkel defect
(c) Both Frenkel and Schottky defects
(d) cation excess defect

Answer

Ans. (c)


Q.32. Which of the following will have metal deficiency defect?
(a) NaCl
(b) FeO
(c) KCl
(d) ZnO

Answer

Ans. (b)


Q.33. In which pair most efficient packing is present?
(a) hep and bcc
(b) hep and ccp
(c) bcc and ccp
(d) bcc and simple cubic cell

Answer

Ans. (b)


Q.34. What is the effect of Frenkel defect on the density of ionic solids?
(a) The density of the crystal increases
(b) The density of the crystal decreases
(c) The density of the crystal remains unchanged
(d) There is no relationship between density of a crystal and defect present in it

Answer

Ans. (c)


Q.35. In a Schottky defect
(a) an ion moves to interstitial position between the lattice points
(b) electrons are trapped in a lattice site
(c) some lattice sites are vacant
(d) some extra cations are present in interstitial space

Answer

Ans. (c)


Q.36. To get n-type of semiconductor, germanium should be doped with
(a) gallium
(b) arsenic
(c) aluminium
(d) boron

Answer

Ans. (b)



Q,37. Iodine molecules are held in the crystals lattice by ________.
(a) london forces
(b) dipole-dipole interactions
(c) covalent bonds
(d) coulombic forces

Answer

Ans. (a)


Q.38. Which of the following is not the characteristic of ionic solids?
(a) Very low value of electrical conductivity in the molten state.
(b) Brittle nature.
(c) Very strong forces of interactions.
(d) Anisotropic nature.

Answer

Ans. (a)


Q.39. In face-centred cubic lattice, a unit cell is shared equally by how many unit cells
(a) 2
(b) 4
(c) 6
(d) 8

Answer

Ans. (c)


Q.40. The number of atoms per unit cell of bcc structure is
(a) 1
(b) 2
(c) 4
(d) 6

Answer

Ans. (b)


Frequently Asked Questions – FAQs

What are Solids?

Solids have definite mass, volume and shape due to the fixed position of their constituent particles,
small intermolecular distances and strong intermolecular forces between them.

“Crystalline solids are anisotropic in nature.” What does this statement mean?

Crystalline solids are anisotropic in nature because of different arrangements of particles in different directions. Some of their physical properties like electrical conductivity, refractive index, etc., shows different values in different directions in the same crystals.

Some of the very old glass objects appear slightly milky instead of being transparent.

Some of the glass objects from ancient monuments look milky instead of being transparent because it undergoes heating during the day and cooling at night i.e., annealing over a number of years. As a result, it acquires some crystalline character. They become a bit opaque.

Give an example each of a molecular solid and an ionic solid.

Molecular solids : HCl, SO2, H2O (any one)
Ionic solids : KCl, CuSO4, ZnS (any one)

What type of interactions holds the molecules together in a polar molecular solid?

Strong dipole-dipole interactions

What are primitive unit cells.

A unit cell in which constituent particles (lattice points) are present only at the corner positions is called primitive or simple unit cell.

How many atoms are there in one unit cell of a body centred cubic crystal?

2 atoms

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15075

Class 12 Chemistry Ch-Surface Chemistry (MCQ)

Class 12 Chemistry Ch-Surface Chemistry (MCQ)

Tue, 18 Feb 2020 12: 36: 08 +0000

Class 12 Chemistry Ch-Surface Chemistry (MCQ)

1. Which of the following process does not occur at the interface of phases?(i) crystallisation(ii) heterogenous catalysis(iii) homogeneous catalysis(iv) corrosion Answer Answer: (iii) homogeneous catalysis Explanation: In homogeneous catalysis, only, the reactant and product are in same phase and composition is uniform throughout. 2. At the equilibrium position in the process of adsorption _.(i) ΔH … Continue reading Class 12 Chemistry Ch-Surface Chemistry (MCQ)

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1. Which of the following process does not occur at the interface of phases?
(i) crystallisation
(ii) heterogenous catalysis
(iii) homogeneous catalysis
(iv) corrosion

Answer

Answer: (iii) homogeneous catalysis

Explanation: In homogeneous catalysis, only, the reactant and product are in same phase
and composition is uniform throughout.

2. At the equilibrium position in the process of adsorption _.
(i) ΔH > 0
(ii) ΔH = TΔS
(iii) ΔH > TΔS
(iv) ΔH < TΔS

Answer

Answer: Ans. (ii) ΔH = TΔS

Explanation: At equilibrium ΔG=0

ΔG=ΔH-TΔS

Therefore, ΔH=TΔS

3. Which of the following interface cannot be obtained?
(i) liquid-liquid
(ii) solid-liquid
(iii) liquid-gas
(iv) gas-gas

Answer

Answer: (iv) gas-gas

Explanation: Because gas-gas forms homogeneous composition.

4. The term ‘sorption’ stands for __.
(i) absorption
(ii) adsorption
(iii) both absorption and adsorption
(iv) desorption

Answer

Answer: (iii) both absorption and adsorption

Explanation: When adsorption and absorption occur simultaneously it is known as sorption.

5. Extent of physisorption of a gas increases with _.
(i) increase in temperature.
(ii) decrease in temperature.
(iii) decrease in surface area of adsorbent.
(iv) decrease in strength of van der Waals forces.

Answer

Answer: (ii) decrease in temperature.

Explanation: Since the adsorption (Solid+ Gas=Gas/Solid+ Heat) process is exothermic, the
physical adsorption occurs readily at low temperature and decreases with increasing
temperature as the equilibrium will shift in backward direction. (Le-Chatelier’s principle).

6. Extent of adsorption of adsorbate from solution phase increases with __.
(i) increase in amount of adsorbate in solution.
(ii) decrease in surface area of adsorbent.
(iii) increase in temperature of solution.
(iv) decrease in amount of adsorbate in solution.

Answer

Answer: (i) increase in amount of adsorbate in solution.

Explanation: The extent of adsorption depends on the concentration of the solute in solution
as the concentration of adsorbate increase interaction between adsorbate and adsorbent
increases thus the extent of adsorption increases.

7. Which one of the following is not applicable to the phenomenon of adsorption?
(i) ΔH > 0
(ii) ΔG < 0
(iii) ΔS < 0
(iv) ΔH < 0

Answer

Answer: (i) ΔH > 0

Explanation: Since adsorption is an exothermic process ΔH cannot be greater than zero.

8. Which of the following is not a favourable condition for physical adsorption?
(i) high pressure
(ii) negative ΔH
(iii) higher critical temperature of adsorbate
(iv) high temperature

Answer

Answer: (iv) high temperature

Explanation: High temperature is not favourable for physical adsorption since it is an
exothermic process.

9. Physical adsorption of a gaseous species may change to chemical adsorption with
__.
(i) decrease in temperature
(ii) increase in temperature
(iii) increase in surface area of adsorbent
(iv) decrease in surface area of adsorbent

Answer

Answer: (ii) increase in temperature

Explanation: On increasing the temperature activation energy of the adsorbate molecule increases. Which can convert physical adsorption into chemisorptions.

10. In physisorption adsorbent does not show specificity for any particular gas because
__.
(i) involved van der Waals forces are universal.
(ii) gases involved behave like ideal gases.
(iii) enthalpy of adsorption is low.
(iv) it is a reversible process.

Answer

Answer: (i) involved van der Waals forces are universal.

11. Which of the following is an example of absorption?
(i) Water on silica gel
(ii) Water on calcium chloride
(iii) Hydrogen on finely divided nickel
(iv) Oxygen on metal surface

Answer

Answer: (ii) Water on calcium chloride

Explanation: Absorption implies that a substance is uniformly distributed, through the body
of the solid or liquid.

12. On the basis of data given below predict which of the following gases shows least
adsorption on a definite amount of charcoal?

(i) CO2
(ii) SO
(iii) CH4
(iv) H2

Answer

Answer: (iv) H2

Explanation: Lesser the value of critical temp of gases lesser will the force of attraction
among molecules and least will be the adsorption.

13. In which of the following reactions heterogenous catalysis is involved?
(a) 2SO2(g) + O2(g)→2SO2(g)
(b) 2SO2(g)→2SO3(g)
(c) N2(g) + 3H2(g)→2NH3(g)
(d) CH3COOCH3(l) + H2O(l) HCI → CH3COOH(aq) + CH3OH(aq)
(i) (b), (c)
(ii) (b), (c), (d)
(iii) (a), (b), (c)
(iv) (d)

Answer

Answer: (i) (b), (c)

Explanation: When the reactant and catalyst are in different phase it is known as
heterogeneous catalysis.

14. At high concentration of soap in water, soap behaves as __.
(i) molecular colloid
(ii) associated colloid
(iii) macromolecular colloid
(iv) lyophilic colloid

Answer

Answer: (ii) associated colloid <br.
Explanation: There are some substances which at low concentrations behave as normal
strong electrolytes, but at higher concentrations exhibit colloidal behavior due to the
formation of aggregates. The aggregated particles thus formed are called micelles. These are
also known as associated colloids.

15. Which of the following will show Tyndall effect?

(i) Aqueous solution of soap below critical micelle concentration.
(ii) Aqueous solution of soap above critical micelle concentration.

(iii) Aqueous solution of sodium chloride.
(iv) Aqueous solution of sugar.

Answer

Answer: (ii) Aqueous solution of soap above critical micelle concentration

Explanation: Tyndall effect is the optical property shown by the colloidal particle. Above
critical micelle concentration, a solution of soap behave as associated colloid that is why it
shows tyndall effect.

16. Method by which lyophobic sol can be protected.
(i) By addition of oppositely charged sol.
(ii) By addition of an electrolyte.
(iii) By addition of lyophilic sol.
(iv) By boiling.

Answer

Answer: (iii) By addition of lyophilic sol.

Explanation: Lyophilic colloids have a unique property of protecting lyophobic colloids.
When a lyophilic sol is added to the lyophobic sol, the lyophilic particles form a layer around
lyophobic particles and thus protect the latter from electrolytes. Lyophilic colloids used for
this purpose are called protective colloids.

17. Freshly prepared precipitate sometimes gets converted to colloidal solution by __.
(i) coagulation
(ii) electrolysis
(iii) diffusion
(iv) peptisation

Answer

Answer: (iv) peptisation

Explanation: Peptisation is the process in which freshly prepared precipitate can be
converted into colloidal solution.

18. Which of the following electrolytes will have maximum coagulating
valueforAgI/Ag+sol?

(i) Na2S
(ii) Na3PO4
(iii) Na2SO4
(iv) NaCl

Answer

Answer: (ii) Na3PO4

Explanation: Higher the value of oppositely charge electrolyte faster will be the rate of
coagulation.

19. A colloidal system having a solid substance as a dispersed phase and a liquid as a
dispersion medium is classified as __.
(i) solid sol
(ii) gel
(iii) emulsion
(iv) sol

Answer

Answer: (iv) sol

Explanation: Solid + liquid= sol (here solid is the dispersed phase and liquid is the dispersion
medium.)

20. The values of colligative properties of colloidal solution are of small order in
comparison to those shown by true solutions of same concentration because of
colloidal particles ______.
(i) exhibit enormous surface area.
(ii) remain suspended in the dispersion medium.
(iii) form lyophilic colloids.
(iv) are comparatively less in number.

Answer

Answer: (iv) are comparatively less in number.

Explanation: Colloidal particles being bigger aggregates, the number of particles in a
colloidal solution is comparatively small as compared to a true solution. Hence, the values of
colligative properties (osmotic pressure, lowering in vapour pressure, depression in freezing
point and elevation in boiling point) are of small order as compared to values shown by true
solutions at same concentration.

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Chemistry MCQs for Class 12 with Answers Chapter 14 Biomolecules

Chemistry MCQs for Class 12 with Answers Chapter 14 Biomolecules

Fri, 14 Feb 2020 10: 20: 48 +0000

Chemistry MCQs for Class 12 with Answers Chapter 14 Biomolecules

MCQs Based On Class 12 Chemistry Chapter 14 Biomolecules MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on chapter 14 Biomolecules will also help students in understanding the … Continue reading Chemistry MCQs for Class 12 with Answers Chapter 14 Biomolecules

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MCQs Based On Class 12 Chemistry Chapter 14 Biomolecules

MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on chapter 14 Biomolecules will also help students in understanding the concepts very well.

Q.1. Glycogen is a branched chain polymer of α-D-glucose units in which chain is formed by C1—C4 glycosidic linkage whereas branching occurs by the formation of C1-C6 glycosidic linkage. Structure of glycogen is similar to _____________________ .
(i) Amylose
(ii) Amylopectin
(iii) Cellulose
(iv) Glucose

Answer

Answer: (ii) Amylopectin

Explanation: Polysaccharides contain a large number of monosaccharide units joined together by glycosidic linkages. These are the most commonly encountered carbohydrates in nature. Amylopectin is insoluble in water and constitutes about 80-85% of starch. It is a branched chain polymer of alpha-D-glucose units in which chain is formed by C1-C4 glycosidic linkage whereas branching occurs by C1-C6 glycosidic linkage.

Q.2. Which of the following polymer is stored in the liver of animals?
(i) Amylose
(ii) Cellulose
(iii) Amylopectin
(iv) Glycogen

Answer

Answer: (iv) Glycogen

Explanation: The carbohydrates are stored in animal body as glycogen. It is also known as animal starch because its structure is similar to amylopectin and is rather more highly branched. It is present in liver, muscles and brain.

Q.3. Sucrose (cane sugar) is a disaccharide. One molecule of sucrose on hydrolysis gives
(i) 2 molecules of glucose
(ii) 2 molecules of glucose + 1 molecule of fructose
(iii) 1 molecule of glucose + 1 molecule of fructose
(iv) 2 molecules of fructose

Answer

Answer: (iii) 1 molecule of glucose + 1 molecule of fructose

Explanation: One of the common disaccharides is sucrose which on hydrolysis gives equimolar mixture of D-(+)-glucose and D-(-) fructose.

C12H22O11 (Sucrose) + H2O → C6H12O6(D-(+)-glucose) + C6H12O6 (D-(-) fructose)

Q.4. Which of the following pairs represents anomers?

Answer

Answer: (iii)

Explanation: The two cyclic hemiacetal forms of glucose differ only in the configuration of the hydroxyl group at Cl, called anomeric carbon (the aldehyde carbon before cyclisation). Such isomers, i.e., alpha-form and beta-form, are called anomers.

Q.5. Proteins are found to have two different types of secondary structures viz. α-helix and β-pleated sheet structure. α-helix structure of protein is stabilised by:
(i) Peptide bonds
(ii) van der Waals forces
(iii) Hydrogen bonds
(iv) Dipole-dipole interactions

Answer

Answer: (iii) Hydrogen bonds

Explanation: α-helix and β-pleated sheet structure: These structures arise due to the regular folding of the backbone of the polypeptide chain due to hydrogen bonding between
>C—O and —NH— group of the peptide bond.

α-Helix is one of the most common ways in which a polypeptide chain forms all possible hydrogen bond by twisting into a right-handed screw (helix) with the -NH group of each amino acid residue hydrogen bonded to the >C=O of an adjacent turn of the helix.

Q.6. In disaccharides, if the reducing groups of monosaccharides i.e. aldehydic or ketonic groups are bonded, these are non-reducing sugars. Which of the following disaccharide is a non-reducing sugar?

Answer

Answer: (ii)

Explanation: One of the common disaccharides is sucrose which on hydrolysis gives equimolar mixture of D-(+)-glucose and D-(-) fructose. These two monosaccharides are held together by a glycosidic linkage between Cl of α-glucose and C2 of beta-fructose.
Since the reducing groups of glucose and fructose are involved in glycosidic bond formation, sucrose is a non-reducing sugar.

Q.7. Which of the following acids is a vitamin?
(i) Aspartic acid
(ii) Ascorbic acid
(iii) Adipic acid
(iv) Saccharic acid

Answer

Answer: (ii) Ascorbic acid

Explanation: Vitamin C is also known as Ascorbic acid.

Q.8. Dinucleotide is obtained by joining two nucleotides together by phosphodiester linkage. Between which carbon atoms of pentose sugars of nucleotides are these linkages present?
(i) 5′ and 3′
(ii) 1′ and 5′
(iii) 5′ and 5′
(iv) 3′ and 3′

Answer

Answer: (i) 5′ and 3′

Explanation: Nucleotides are joined together by phosphodiester linkage between 5’ and 3’ carbon atoms of the pentose sugar.

Q.9. Nucleic acids are the polymers of
(i) Nucleosides
(ii) Nucleotides
(iii) Bases
(iv) Sugars

Answer

Answer: (ii) Nucleotides

Explanation: Nucleic acids are long chain polymers of nucleotides, so they are also called polynucleotides.

Q.10. Which of the following statements is not true about glucose?
(i) It is an aldohexose.
(ii) On heating with HI it forms n-hexane.
(iii) It is present in furanose form.
(iv) It does not give 2,4-DNP test.

Answer

Answer: (iii)

Explanation: Fructose is present in furanose form.

Q.11. Each polypeptide in a protein has amino acids linked with each other in a specific sequence. This sequence of amino acids is said to be
(i) primary structure of proteins.
(ii) secondary structure of proteins.
(iii) tertiary structure of proteins.
(iv) quaternary structure of proteins.

Answer

Answer: (i) primary structure of proteins.

Explanation: Sequence of amino acids is said to be primary structure of proteins.

Q.12. DNA and RNA contain four bases each. Which of the following bases is not present in RNA?
(i) Adenine
(ii) Uracil
(iii) Thymine
(iv) Cytosine
Ans. (iii) Thymine

Answer

Answer: (iii) Thymine

Explanation: DNA contains four bases viz. adenine (A), guanine (G), cytosine (C) and thymine (T). RNA also contains four bases; the first three bases are same as in DNA but the fourth one is uracil (U).

Q.13. Which of the following B group vitamins can be stored in our body?
(i) Vitamin B1
(ii) Vitamin B2
(iii) Vitamin B6
(iv) Vitamin B12

Answer

Answer: (iv) Vitamin B12

Explanation: Water soluble vitamins must be supplied regularly in diet because they are readily excreted in urine and cannot be stored (except vitamin B12) in our body.

Q.14. Which of the following bases is not present in DNA?
(i) Adenine
(ii) Thymine
(iii) Cytosine
(iv) Uracil

Answer

Answer: (iv) Uracil

Explanation: Uracil is present in RNA but not in DNA.

Q15. Three cyclic structures of monosaccharides are given below which of these are anomers.

(i) I and II
(ii) II and III
(iii) I and III
(iv) III is anomer of I and II

Answer

Answer: (i) I and II

Explanation: This behavior could not be explained by the open chain structure (I) for glucose. It was proposed that one of the —OH groups may add to the —CHO group and form a cyclic hemiacetal structure. It was found that glucose forms a six-membered ring in which
—OH at C-5 is involved in ring formation. This explains the absence of —CHO group and also existence of glucose in two forms as shown below.

Q.16. Which of the following reactions of glucose can be explained only by its cyclic structure?
(i) Glucose forms pentaacetate.
(ii) Glucose reacts with hydroxylamine to form an oxime.
(iii) Pentaacetate of glucose does not react with hydroxylamine.
(iv) Glucose is oxidised by nitric acid to gluconic acid.

Answer

Answer: (iii) Pentaacetate of glucose does not react with hydroxylamine.

Explanation: The pentaacetate of glucose does not react with hydroxylamine indicating the absence of free —CHO group.

Q.17. Optical rotations of some compounds along with their structures are given Below. Which of them have D configuration?

(i) I, II, III
(ii) II, III
(iii) I, II
(iv) III

Answer

Answer: (i) I, II, III

Explanation: All those compounds which can be chemically correlated to (+) isomer of glyceraldehyde are said to have D-configuration whereas those which can be correlated to (-) isomer of glyceraldehyde are said to have L-configuration.

Q.18. Structure of a disaccharide formed by glucose and fructose is given below. Identify anomeric carbon atoms in monosaccharide units.

(i) ‘a’ carbon of glucose and ‘a’ carbon of fructose.
(ii) ‘a’ carbon of glucose and ‘e’ carbon of fructose.
(iii) ‘a’ carbon of glucose and ‘b’ carbon of fructose.
(iv) ‘f’ carbon of glucose and ‘f’ carbon of fructose.

Answer

Answer: (iii) ‘a’ carbon of glucose and ‘b’ carbon of fructose.

Explanation: Two monosaccharides are held together by a glycosidic linkage between Cl of α-glucose and C2 of β-fructose.

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