Chemistry-(general)

NEET Chemistry (general) MCQ Question

Type: MCQ-conceptual-Hard-Class 12

Which combinations of statements accurately describe the characteristics of first-order reactions?

A

The half-life is constant and independent of initial concentration; time for 99.9% completion is 10 times the half-life.

B

The rate constant depends on the initial concentration; the half-life increases with decreasing concentration.

C

The time required for completion of 99.9% of the reaction is equal to the half-life; the rate constant is variable.

D

The half-life is dependent on the temperature; the time for 99.9% completion is less than 10 times the half-life.

Correct Answer

Option A

Detailed Explanation

In a first-order reaction, the half-life is indeed constant and does not depend on the initial concentration, and the time for 99.9% completion is 10 times the half-life, as indicated in the NCERT context.

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