Question

A substance undergoes first order decomposition. The decomposition follows two parallel first-order reactions as shown in figure.
The percentage distribution of B and C are:

• 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

The correct option is B $76.83\%B$ and $23.17\%C$

$\%$ distribution of $B=\frac{K_1}{K_1+K_2}\times 100$

$=\frac{1.26\times {10}^{-4}}{1.26\times {10}^{-4}+3.8\times {10}^{-5}}\times 100$

$B\%=76.83\%$

$\%$ Distribution of $C=\frac{K_2}{K_1+K_2}\times 100$

$=\frac{3.8\times {10}^{-4}}{1.26\times {10}^{-4}+3.8\times {10}^{-5}}\times 100$

$C\%=23.17\%$
Option C is correct.