Question

$A_{\left(g\right)}\to B_{\left(g\right)}$ is a first order reaction. The initial concentration of A is 0.2mol $l^{-1}$ . After 10 minutes, the concentration of B is found to be 0.18mol $l^{-1}$ . Calculate rate constant of the reaction?

• A. 0.2303
• B. 2.303
• C. 0.693
• D. 0.01

Answer 1

The correct option is A 0.2303

At t=0, $\left[A\right]=0.2$ and $\left[B\right]=0.$
At t=10 min, $\left[A\right]=0.2-0.18=0.02$, $\left[B\right]=\mathrm{0.18.}$
$k=\frac{1}{t}ln\frac{\left[C_o\right]}{[C_o-C_t]}=\frac{1}{10}ln\frac{\left[0.2\right]}{\left[0.02\right]}=\mathrm{0.2302.}$