Question

In a first order reaction, the time required to reduce the concentration of reactant from 1 mol/lit. to 0.5 mol/lit. will be ____ that required to reduce it from 10 mol/lit. to 5 mol/lit. in the same volume

• A. More than
• B. Less than
• C. Same as
• D. Data insufficient and cannot be determined

Hint:

In first-order kinetics, time depends on ratio, not absolute concentrations.

Answer 1

The Correct Option is C

For first order: \( t = \frac{2.303}{k} \log \frac{[A]_0}{[A]} \)
Here, the ratio is the same (2:1) in both cases, hence same time.