Question

The substance undergoes first order decomposition. The decomposition follows two parallel first order reactions as :

$K_{1}\text{ = 1.26 }\text{×}\text{ 1}\text{0}^{\text{-4}}\text{ se}\text{c}^{\text{-1}}\text{ and }\text{K}_{2}\text{ = 3.8 }\text{×}\text{ 1}\text{0}^{\text{-5}}\text{ se}\text{c}^{\text{-1}}$

The percentage distribution of B and C

• A. 80% B and 20% C
• B. 76.83% B and 23.17%C
• C. 90% B and 10% C
• D. 60% B and 40% C

Answer 1

Answer: (B)

76.83% B and 23.17%C

Answer 2

$\% ofB = \frac{k_{1} \times 100}{k_{1} + k_{2}} = \frac{1.26 \times 10^{- 4} \times 100}{12.6 \times 10^{- 5} + 3.8 \times 10^{- 5}} = 76.83\%.$

$\% ofC = \frac{k_{2} \times 100}{k_{1} + k_{2}} = \frac{3.8 \times 10^{- 5} \times 100}{12.6 \times 10^{- 5} + 3.8 \times 10^{- 5}} = 23.17\%$