Question

For the reaction 2A + B → A₂B find the rate of decrease of [B].

Options

• half the rate of [A] decreases

• same as rate of [A] decreases

• twice the rate of [A] decreases

• double the rate of [A₂B] increases

Answer 1

half the rate of [A] decreases

Explanation:

\[2\mathrm{A}+\mathrm{B}\longrightarrow\mathrm{A}_2\mathrm{B}\]
\[\mathrm{Rate}=-\frac{1}{2}\frac{\mathrm{d[A]}}{\mathrm{dt}}=-\frac{\mathrm{d[B]}}{\mathrm{dt}}=\frac{\mathrm{d[A_{2}B]}}{\mathrm{dt}}\]
Thus, \[\frac{1}{2}\] rate of disappearance of A
= rate of disappearance of B.