Question

Gaseous reaction A $\to$ B + C follows first order kinetics. Concentration of A changes from 1 M to 0.25 M in 138.6 minutes. Find the rate of reaction when concentration of A is 0.1 M.

• A. $2\times {10}^{-3}M/min$
• B. ${10}^{-3}M/min$
• C. ${10}^{-4}M/min$
• D. $5\times {10}^{-4}M/min$

Answer 1

The correct option is B ${10}^{-3}M/min$

$2t_{1/2}=138.6t_{1/2}=\frac{138.6}{2}K=\frac{0.693}{t_{1/2}}R=K.\left[A\right]=\frac{0.693}{69.3}\times 0.1={10}^{-3}M/min$