Question

*If the rate constant for a first order reaction is 0.693 s⁻¹, then half-life period will be:* 1️⃣ 10 sec 2️⃣ 10 min 3️⃣ 1 min 4️⃣ 1 sec​

Answer 1

Given:

The rate constant for a first-order reaction is 0.693 s⁻¹.

To Find:

The half-life period of the reaction.

Solution:

To find the half-life period we will follow the following steps:

As we know,

The half-life for a first-order reaction is given by:

$Half-life × time = 0.693$

$half \: life = \frac{0.693}{time}$

$time = \frac{0.693}{half \: life}$

$time = \frac{0.693}{0.693}$

$time = 1sec$

Henceforth, the half life period for the reaction is (3) 1 sec.