Ncert Exercises & Solutions

4.13 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

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

(i) H a l f l i f e,

= \frac{0.693}{200 s^{- 1}}

= 3.47 s (a p p r o x i m a t e l y)

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

(i i) H a l f l i f e,

= \frac{0.693}{2 m i n^{- 1}}

= 0.35 m i n (a p p r o x i m a t e r l y)

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

= \frac{0.693}{4 y e a r s^{- 1}}

= 0.173 years (approximately)