Decomposition of H2O2 follows a first order reaction. In fifty minutes the concentration

• Chemical Kinetics

Decomposition of H₂O₂ follows a first order reaction. In fifty minutes the concentration of H₂O₂ decreases from 0.5 to 0.125 M in one such decomposition. When the concentration of H₂O₂ reaches 0.05 M, the rate of formation of O₂ will be:

1. 6.93 × 10^–4 mol min^–1
2. 2.66 L min^–1 at STP
3. 1.34 × 10^–2 mol min^–1
4. 6.93 × 10^–2 mol min^–1

Solution

Decomposition reaction of H₂O₂ is:

\( \ce{H2O2 -> H2O + 1/2O2} \)

2t_½ =  50 mins

t_½ = 25 mins

For first order reaction,

t_½ = 0.693/k

k = 0.693/25

\( \dfrac{d[H_2O_2]}{dt} = \dfrac{d[O_2]}{dt} \times 2 \)

\( \dfrac{d[O_2]}{dt} = \dfrac{1}{2} \times \dfrac{0.693}{25} \times 0.05 \)

= 6.93 × 10^–4

The correct option is A.