Question

For a chemical reaction,
$m A \rightarrow xB$, the rate law is $r=k[A]^2$.
If the concentration of $A$ is doubled, the reaction rate will be,

• A. Doubled
• B. Quadrupled
• C. Increases by 8 times
• D. Unchanged

Answer 1

Answer: (B)

$\because r=k[A]^{2}$ means $r \propto[A]^{2}$

Thus, when concentration of $A$ is doubled,

$r \propto[2 A]^{2} \propto 4[A]^{2}$

Hence. rate becomes quadrupled.