Question

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

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

Answer 1

Answer: (B)

twice the rate that $B$ will decrease

According to the given equation, the rate of disappearance of reactant $A$ is twice the rate of disappearance of reactant $B$.
$⟹\frac{-1}{2}\frac{d\left[A\right]}{dt}=\frac{-d\left[B\right]}{dt}=\frac{d\left[A_{2}B\right]}{dt}$