Question

For a chemical reaction,
$mA\to xB$, 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,

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

Hence. rate becomes quadrupled.