Question

For the reaction $A+2B\to C$, the reaction rate is doubled, if the concentration of $A$ is doubled. The rate is increased by four times when the concentration of both $A$ and $B$ are increased by four times. The order of the reaction is:

• A. 3
• B. 0
• C. 1
• D. 2

Answer 1

The correct option is C 1

For the reaction $A+2B\to C$, the reaction rate is doubled, if the concentration of $A$ is doubled.
This indicates that the reaction is of first order with respect to $A$.

The rate is increased by four times when the concentration of both $A$ and $B$ are increased by four times.
This indicates that the reaction is of zero-order with respect to $B$.

(Note: when the concentration of $A$ is increased by four times, the rate is increased by four times.
Hence, when the concentration of $B$ is increased by four times, the rate is not increased.)

The order of the reaction is $1+0=1$