Question

A reaction A $\to$ B follows a second order kinetic. Doubling the concentration of A will increase the rate of formation of B by a factor of:

• A. 1/4
• B. 4
• C. 1/2
• D. 2

Answer 1

The correct option is B 4

For second order A $\to$ B

reaction rate $=r_1$

$r_1=k[A{]}^2$ ........ (1)

When concentration of A is doubled then rate becomes $r_2$

$r_2=k[2A{]}^2=4k[A{]}^2$ ......... (2)

Dividing equation (2) by equation (1),

$\frac{r_1}{r_2}=4$ or $r_2=4r_1$

$\therefore$ Rate of formation of B increases by factor of 4 when concentration of A is doubled.