-->

Chemical Kinetics

Question

Calculate the half life of a first order reaction from their rate constants given below:
(i) 200 s^–1 (ii) 2 min^–1 (iii) 4 years^–1

Solution

For the first order reaction.

t_{1 / 2} = \frac{0.693}{k}

(a)

K = 200 s^{- 1} ∴ t_{1 / 2} = \frac{0.693}{200} = 3.465 \times 10^{- 3} s

(b)

K = 2 \min^{- 1} ∴ t_{1 / 2} = \frac{0.693}{2} = 0.3465 \min

(c)

K = 4 years^{- 1} ∴ t_{1 / 2} = \frac{0.693}{4} = 0.1732 years .