Chemistry - Chemical Kinetics Question with Solution | TestHub

For a zero-order reaction $2\text{A}\to \text{B}$, the rate of reaction is expressed as:

$\text{Rate}=-\frac{1}{2}\frac{d[\text{A}]}{dt}=k$

$\Rightarrow -\frac{d[\text{A}]}{dt}=2k$

Integrating this equation, we get the integrated rate law:

$[\text{A}{]}_0-[\text{A}{]}_t=2kt$

Given:
Initial concentration, $[\text{A}{]}_0=2$ M
Rate constant, $k=1.0$ mol L${}^{-1}$ min${}^{-1}$

For $75\%$ completion of the reaction, the amount of A reacted is:

$[\text{A}{]}_0-[\text{A}{]}_t=\frac{75}{100}\times 2=1.5$ M

Substituting these values into the integrated rate equation:

$1.5=2\times 1.0\times t$

$2t=1.5$

$t=0.75$ min