Assertion (A) & Reason (B) MCQ

Question 11 Mark

Assertion $(A): RCHO, RCOCH_3 $ and cyclic ketones react with sodium bisulphite.
Reason $(R):$ Crystalline solid derivatives are formed when aldehydes or ketones are shaken with saturated aqueous solution of sodium bisulphite.

Answer

$\mathrm{SO}_3^{--}$ is a large ion. Its addition is possible only under the condition that

grouping is not sterically hindered as is the case for $RCHO, RCOCH_3$ and cyclic ketones.

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Question 21 Mark

Assertion (A): Primary structure of proteins gives an idea about the conformation of the molecule.
Reason (R): The differences in chemical and biological properties of various proteins arise due to the difference in primary structure.

Answer

(d) A is false but R is true.
Explanation: The primary structure of a protein gives only the nature of linkages of -amino acids in a protein chain.

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Question 31 Mark

Assertion $(A):$ Last traces of moisture in ethanol can be removed by keeping it over sodium wire
Reason $(R):$ Sodium reacts with water but not with ethanol to produce $H_2$ gas.

Answer

Last traces of moisture in ethanol cannot be removed by keeping it over sodium wire. Sodium reacts both with $H_2O$ and ethanol.

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Question 41 Mark

Assertion (A): Aryl halide gives a mixture of o- and p-products.
Reason (R): Aryl halides undergo electrophilic substitutions more readily than benzene.

Answer

(c) A is true but R is false.
Explanation: Halogens are somewhat deactivating but o, p-directing. As a result, aryl halides undergo the usual electrophilic substitution reactions less readily than benzene

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Chemistry Assertion (A) & Reason (B) MCQ

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