AIIMS2018Chemistry-Organic Chemistry

AIIMS 2018 Chemistry Amino Acids Assertion Reason Question

Type: Assertion Reason-conceptual-Medium-Class 11

Assertion: The value of enthalpy neutralization of weak acid and strong base is numerically less than 57.1 kJ.

Reason: All the OH\text{OH}^{−} ions furnished by 1g equivalent of strong base are not completely neutralized.

A

If both assertion and reason are true and reason is the correct explanation of assertion.

B

If both assertion and reason are true but reason is not the correct explanation of assertion.

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Correct Answer

Option C

Detailed Explanation

Tyrosine does not behave as an acid at pH 7; instead, it acts as a weak base due to the presence of its amino group (–NH₂) and the pKₐ of the phenolic hydroxyl group (–OH) being around 10.1, which is greater than 7, indicating that the phenol moiety is largely unprotonated at physiological pH. Therefore, while the assertion is true, the reason is false, making option C correct. Options A and B are incorrect because they incorrectly assert that the reason explains the assertion, and option D is incorrect as it misrepresents the truth of the assertion.

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