Consider the reaction $2 \mathrm{~A}+2 \mathrm{~B} \rightarrow \mathrm{C}+2 \mathrm{D}$. If the…
Consider the reaction $2 \mathrm{~A}+2 \mathrm{~B} \rightarrow \mathrm{C}+2 \mathrm{D}$. If the concentration of $\mathrm{A}$ is doubled at constant $\mathrm{B}$, the rate increases by a factor 4 . If the concentration of $\mathrm{B}$ is doubled at constant $A$, rate is doubled. What is the rate law?
$r=k[A]^{2}[B]^{2}$
$r=k[A]^{4}[B]^{2}$
$r=k[A][B]^{2}$
$r=k[A]^{2}[B]$
Solution
Consider the reaction $2 A + 2 B \rightarrow C + 2 D$, if concentration of A is doubled at constant $[B]$, rate increases by a factor 4. If concentration B is doubled at constant $[A]$ the rate is doubled. Rate law of the reaction is rate $= k[A]^2 [B]$.