Question

For a reaction
$2A+B\to C+D$, the active mass of $B$ is kept constant but that of $A$ is tripled. The rate of reaction will -

• A. Decrease by $3$ times
• B. Increased by $9$ times
• C. Increase by $3$ times
• D. Unpredictable

Answer 1

The correct option is B Increased by $9$ times

According to the given reaction, $Rate=k\left[A{]}^2\right[B{]}^1$

When A becomes 3A i.e. triples, the rate will become: $Rat{e}^{{}^{\prime }}=k\left[3A{]}^2\right[B{]}^1=9k\left[A{]}^2\right[B]$

Thus, rate of reaction is increased by 9 times.