Question

The reaction $2A+B+C\to D+E$ is found to be first order in $A$ , second in $B$ and zero order in $C$ . What is the effect on the rate of increasing concentration of $A$ , $B$ and $C$ two times?

• A. 72 times
• B. 8 times
• C. 24 times
• D. 36 times
• E. none of the these

Answer 1

Answer: (B)

The rate law for the reaction is as: $r=\frac{dx}{dt}=k(A){(B)}^2{(C)}^0=k(A){(B)}^2$
On increasing the concentrations of A, B and C two times.
$r=\frac{dx}{dt}=k(2A){(2B)}^2{(2C)}^0$ $=8k(A){(B)}^2$
Thus, the rate increases eight times.