Question

50% of a first order reaction is completed in 30 min. The velocity constant of the reaction is:

• A. 0.231
• B. 2.31
• C. 0.00231
• D. 0.0231

Answer 1

The correct option is D 0.0231

For a first order reaction, the relation between $t_{1/2}$ and rate constant is $t_{1/2}=\frac{0.693}{k}$

$\Rightarrow k=\frac{0.693}{t_{1/2}}=\frac{0.693}{30}=0.0231{min}^{-1}$