Question

In a reaction, $2A_2+B_2⟶2A_{2}B$, the reactant $A$ will disappear at:

• A. half the rate that $B$ will decrease
• B. the same rate that $B$ will decrease
• C. double the rate that $A_{2}B$ will form
• D. twice the rate that $B$ will decrease

Answer 1

The correct option is D twice the rate that $B$ will decrease

${2A}_2+B_2\to {2A}_{2}B$

For the given reaction we can write

$\frac{-1}{2}\frac{d\left[A_2\right]}{dt}=\frac{-d\left[B_2\right]}{dt}=\frac{1}{2}\frac{d\left[A_{2}B\right]}{dt}$

Hence, rate of disappearance of $A_2=2\times$rate of disappearance of $B$.

Thus, statement $D$ is correct.