Question

In the reaction: P + Q longrightarrow ?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 time as shown in the figure. The overall order of the reaction is: 

• A. \(2\)
• B. \(3\)
• C. \(0\)
• D. 1

Hint:

For second-order reactions: t₇5% = 2t₅0% Zero-order reactions show linear concentration–time plots.

Answer 1

The Correct Option is A

Step 1: From the graph, concentration of Q decreases linearly with time. ⟹ Reaction is zero order with respect to Q
Step 2: Given: t₇5% = 2t₅0% This is a characteristic of a second order reaction with respect to P.
Step 3: Overall order: = order in P + order in Q = 2 + 0 = 2