1.
A substance undergoes first-order decomposition following two parallel first-order reactions:

A→k1=1.26×10−4 s−1B\text{A} \xrightarrow{k_1 = 1.26 \times 10^{-4}\,\text{s}^{-1}} \text{B}


A→k2=3.8×10−5 s−1C\text{A} \xrightarrow{k_2 = 3.8 \times 10^{-5}\,\text{s}^{-1}} \text{C}


The percentage distribution of B and C are