Question

In the reaction, $P+Q\to R+S$, the time taken for 75% reaction of P is twice the time taken for 50% reaction of P. The concentration of Q varies with reaction time as shown in the figure. The overall order of the reaction is:

• A. 2
• B. 3
• C. 0
• D. 1

Answer 1

The correct option is D 1

Overall order reaction can be decided by the data given $t_{75\%}=2t_{50\%}$.

It is a first-order reaction with respect to $P$.

From graph [Q] is linearly decreasing with time, i.e. order of reaction with respect to Q is zero and the rate expression is $r=k\left[P{]}^1\right[Q{]}^0$.

Hence, (D) is correct.