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Multiple Choice Questions
One and More than One Correct
1. $\text{B(OH)}_3 + \text{NaOH} \rightleftharpoons \text{NaBO}_2 + \text{Na[B(OH)}_4] + \text{H}_2\text{O}$
How can this reaction is made to proceed in forward direction? [JEE 2006]
(a) addition of cis 1, 2 diol
(b) addition of borax
(c) addition of trans 1, 2 diol
(d) addition of $\text{Na}_2\text{HPO}_4$
Answer: (a)
Explanation: Due to formation of chelated complex, the reaction moves in forward direction.
2. The molecular formula of a commercial resin used for exchanging ions in water softening is $\text{C}_8\text{H}_7\text{SO}_3\text{Na}$ (Mol. Wt. 206). What would be the maximum uptake of $\text{Ca}^{2+}$ ions by the resin when expressed in mole per gram resin? [JEE Main 2015]
(a) $\frac{1}{103}$
(b) $\frac{1}{206}$
(c) $\frac{2}{306}$
(d) $\frac{1}{412}$
Answer: (d)
Explanation: $2\text{C}_8\text{H}_7\text{SO}_3\text{Na} + \text{Ca}^{2+} \longrightarrow (\text{C}_8\text{H}_7\text{SO}_3)_2\text{Ca} + 2\text{Na}^{+}$. 2 moles of $\text{C}_8\text{H}_7\text{SO}_3\text{Na}$ = $2 \times 206\text{ g}$ = $412\text{ g}$ takes up 1 mole of $\text{Ca}^{2+}$. Therefore, maximum uptake per gram resin = $\frac{1}{412}\text{ mole g}^{-1}$.
3. Which polymer is used in the manufacture of paints and lacquers? [JEE Main 2015]
(a) Bakelite
(b) Glyptal
(c) Polypropene
(d) Poly vinyl chloride
Answer: (b)
Explanation: Glyptal is used in the manufacture of paints and lacquers.
4. Under hydrolytic conditions, the compounds used for preparation of linear polymer and for chain termination, respectively, are [JEE Adv. 2015 P-II]
(a) $\text{CH}_3\text{SiCl}_3$ and $\text{Si(CH}_3)_4$
(b) $\text{(CH}_3)_2\text{SiCl}_2$ and $\text{(CH}_3)_3\text{SiCl}$
(c) $\text{(CH}_3)_2\text{SiCl}_2$ and $\text{(CH}_3)_3\text{SiCl}_2$
(d) $\text{SiCl}_4$ and $\text{(CH}_3)_3\text{SiCl}$
Answer: (b)
Explanation: $\text{(CH}_3)_2\text{SiCl}_2$ on hydrolysis gives a chain extender yielding linear polymers, while $\text{(CH}_3)_3\text{SiCl}$ provides a single reactive terminal group that acts as a chain terminator.
5. Which of the following statements about low density polythene is false? [JEE Main 2016]
(a) Its synthesis requires high pressure
(b) It is poor conductor of electricity
(c) Its synthesis requires dioxygen or a peroxide initiator as a catalyst
(d) It is used in manufacture of buckets, dustbins etc.
Answer: (d)
Explanation: Low density polythene is not used in the manufacturing of buckets, dustbins etc., because buckets and dustbins are manufactured using high density polythene.
6. On complete hydrogenation, natural rubber produces [JEE Adv. 2016 P-I]
(a) ethylene-propylene copolymer
(b) vulcanised rubber
(c) polypropylene
(d) polybutylene
Answer: (a)
Explanation: Natural rubber on complete hydrogenation yields an alternating or random ethylene-propylene-like saturated hydrocarbon copolymer structure.
7. The formation of which of the following polymer involves hydrolysis [JEE Main 2017]
(a) Terylene
(b) Nylon 6
(c) Bakelite
(d) Nylon 6, 6
Answer: (b)
Explanation: Formation of Nylon-6 involves the ring-opening polymerization via hydrolysis of its monomer (caprolactam) in the initial state.
8. The structure of Nylon-6 is: [JEE Main 2019]
(a) $\left[ — (\text{CH}_2)_6 — \text{C}(=\text{O}) — \text{NH} — \right]_n$
(b) $\left[ — (\text{CH}_2)_4 — \text{C}(=\text{O}) — \text{NH} — \right]_n$
(c) $\left[ — \text{C}(=\text{O}) — (\text{CH}_2)_5 — \text{NH} — \right]_n$
(d) $\left[ — \text{C}(=\text{O}) — (\text{CH}_2)_6 — \text{NH} — \right]_n$
Answer: (c)
Explanation: Nylon-6 is a polymer of $\epsilon$-amino caproic acid containing 5 methylene groups in the repeating unit along with the carbonyl and amino-derived linkages: $\left[ — \text{C}(=\text{O}) — (\text{CH}_2)_5 — \text{NH} — \right]_n$.
9. Correct statement among a to d regarding silicones are:
1. They are polymers with hydrophobic character.
2. They are biocompatible.
3. In general, they have high thermal stability and low dielectric strength.
4. Usually, they are resistant to oxidation and used as greases. [JEE Main 2019]
(a) 1, 2, and 3 only
(b) 1 and 2 only
(c) 1, 2, 3 and 4 only
(d) 1, 2 and 4 only
Answer: (c)
Explanation: All listed statements correctly represent the chemical and physical properties and uses of silicones.
10. The major product of the following reaction is: [JEE Main 2019]
(a) Option a structure
(b) Option b structure
(c) Option c structure
(d) Option d structure
Answer: (c)
Explanation: Based on the reaction sequence involving acid treatment and subsequent polymerization, option (c) is obtained as the major product.
11. The polymer obtained from the following reactions is: [JEE Main 2019]
(a) $\left[ — \text{C}(=\text{O}) — (\text{CH}_2)_4 — \text{NH} — \right]_n$
(b) $\left[ — \text{O} — (\text{CH}_2)_4 — \text{C}(=\text{O}) — \right]_n$
(c) $\left[ — \text{HN}\text{C}(=\text{O})(\text{CH}_2)_4 —\text{C}(=\text{O})— \text{N} — \right]_n$
(d) $\left[ — \text{OC}(\text{CH}_2)_4\text{O} — \right]_n$
Answer: (b)
Explanation: The given reactant conditions lead to the formation of the polyester with structural unit $\left[ — \text{O} — (\text{CH}_2)_4 — \text{C}(=\text{O}) — \right]_n$.
12. The homopolymer formed from 4-hydroxybutanoic acid is:- [JEE Main 2019]
(a) $\left[ — \text{C}(=\text{O})(\text{CH}_2)_3 — \text{O} — \right]_n$
(b) $\left[ — \text{OC}(\text{CH}_2)_3 — \text{O} — \right]_n$
(c) $\left[ — \text{C}(=\text{O})(\text{CH}_2)_2 — \text{O} — \right]_n$
(d) $\left[ — \text{C}(=\text{O})(\text{CH}_2)_2 — \text{O} — \right]_n$
Answer: (a)
Explanation: Self-condensation/polymerization of 4-hydroxybutanoic acid ($\text{HO}-\text{CH}_2\text{CH}_2\text{CH}_2-\text{COOH}$) yields the polyester homopolymer $\left[ — \text{C}(=\text{O})(\text{CH}_2)_3 — \text{O} — \right]_n$.
13. Poly-$\beta$-hydroxybutyrate-co-$\beta$-hydroxyvalerate (PHBV) is a copolymer of___. [JEE Main 2019]
(a) 3-hydroxybutanoic acid and 4-hydroxypentanoic acid
(b) 2-hydroxybutanoic acid and 3-hydroxypentanoic acid
(c) 3-hydroxybutanoic acid and 2-hydroxypentanoic acid
(d) 3-hydroxybutanoic acid and 3-hydroxypentanoic acid
Answer: (d)
Explanation: PHBV is a biodegradable copolymer synthesized from 3-hydroxybutanoic acid and 3-hydroxypentanoic acid monomers.
14. The two monomers for the synthesis of Nylon 6, 6 are: [JEE Main 2019]
(a) $\text{HOOC}(\text{CH}_2)_6\text{COOH}, \text{H}_2\text{N}(\text{CH}_2)_6\text{NH}_2$
(b) $\text{HOOC}(\text{CH}_2)_4\text{COOH}, \text{H}_2\text{N}(\text{CH}_2)_4\text{NH}_2$
(c) $\text{HOOC}(\text{CH}_2)_6\text{COOH}, \text{H}_2\text{N}(\text{CH}_2)_4\text{NH}_2$
(d) $\text{HOOC}(\text{CH}_2)_4\text{COOH}, \text{H}_2\text{N}(\text{CH}_2)_6\text{NH}_2$
Answer: (d)
Explanation: Nylon-6,6 is a condensation polymer formed from hexamethylenediamine ($\text{H}_2\text{N}(\text{CH}_2)_6\text{NH}_2$) and adipic acid ($\text{HOOC}(\text{CH}_2)_4\text{COOH}$).
15. Which of the following is/are correct? [JEE Adv. 2019 P-II]
(a) Teflon is formed by polymerization of tetrafluoroethene.
(b) Natural rubber is the trans form of polyisoprene.
(c) Cellulose contains only $\alpha$-D-glucose linkage
(d) Nylon-6 contains amide linkage.
Answer: (a, d)
Explanation: Teflon is produced via polymerization of tetrafluoroethene, and Nylon-6 contains characteristic amide linkages. Natural rubber is cis-polyisoprene, and cellulose contains $\beta$-D-glucose units.
Matrix Match/Column Match
16. Match the chemical substances in Column I with type of polymers/type of bonds in Column II. [JEE 2007 P-I]
Column I: (A) cellulose, (B) nylon-6, 6, (C) protein, (D) sucrose
Column II: 1. natural polymer, 2. synthetic polymer, 3. amide linkage, 4. glycoside linkage
(a) $\text{A} \rightarrow 1,4; \text{B} \rightarrow 2,3; \text{C} \rightarrow 1,3; \text{D} \rightarrow 4$
(b) $\text{A} \rightarrow 1,3; \text{B} \rightarrow 2,4; \text{C} \rightarrow 1,2; \text{D} \rightarrow 4$
(c) $\text{A} \rightarrow 1,2; \text{B} \rightarrow 2; \text{C} \rightarrow 1,3; \text{D} \rightarrow 4$
(d) $\text{A} \rightarrow 1,4; \text{B} \rightarrow 2,3; \text{C} \rightarrow 1,2; \text{D} \rightarrow 1$
Answer: (a)
Explanation: (A) Cellulose is a natural polymer containing glycoside linkages (1, 4). (B) Nylon-6,6 is a synthetic polymer containing amide linkages (2, 3). (C) Protein is a natural polymer containing amide linkages (1, 3). (D) Sucrose contains a glycoside linkage (4).
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