Question

For the given reaction,
$3A+2B\to C+D,$ the experimental rate law is $R=K\left[A{]}^2\right[B{]}^1$. When the active mass of 'B' is kept constant and 'A' is tripled then, the rate of the reaction will

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

Answer 1

The correct option is B Increase by 9 times

For the given reaction, the experimental rate law is,
$Rate=K{\left[A\right]}^2{\left[B\right]}^1$

When the concentration of 'A' is tripled (3A) and 'B' is kept constant,

$Rate=K{\left[3A\right]}^2{\left[B\right]}^1$$=9K{\left[A\right]}^2\left[B\right]$
$Rate=9\times K{\left[A\right]}^2\left[B\right]$
Thus, the rate of reaction is increased by 9 times.