Question

When the concentration of a reactant of first order reaction is doubled, the rate becomes ________ times, but for ___________ order reaction, the rate remains same.

• A. Four; zero
• B. Two; zero
• C. Zero; four
• D. Zero; three

Answer 1

Answer: (B)

Two; zero

When the concentration of a reactant of the first-order reaction is doubled, the rate becomes two times, but for zero-order reaction, the rate remains the same.

For first order reaction,
rate $=k\left[A\right]$
When $\left[A\right]$ is doubled, the rate is doubled.

For zero order reaction,

rate $=k[A{]}^0$
When $\left[A\right]$ is doubled, the rate is unchanged.

So, the correct option is $B$