KVPY Sample Paper KVPY Stream-SX Model Paper-20

In the reaction,

\[P+Q\xrightarrow{{}}R+S\]

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

Correct Answer: D

Solution :

For P, if \[{{\operatorname{t}}_{50%}}=x\]then\[{{t}_{75%}}=2\operatorname{x}\]

This is true only for first order reaction.

So, order with respect to P is 1.

Further the graph shows that concentration of Q decreases with time. So rate, with respect to Q, remains constant. Hence, it is zero order wrt Q.

So, overall order is \[1+0=1\]