NCERT Class XII Chemistry
Chapter - Chemical Kinetics
Questions with Solutions

© examsnet.com
Question : 9
Total: 39
A reaction is first order in A and second order in B.
(i) Write the differential rate equation.
(ii) How is the rate affected on increasing the concentration of B three times?
(iii) How is the rate affected when the concentrations of both A and B are doubled?
Solution:  
(i) Reaction is first order in A and second order in B, hence differentialrate equation is
dx
dt
=k[A][B]2

(ii) Let rate =kab2
If [B] is tripled, Rate =ka(3b)2=9kab2
i.e. Rate increases 9 times.
(iii) If both [A] and [B] are doubled, Rate =k(2a)(2b)2
=8kab2
i.e. Rate of reaction increases 8 times.
© examsnet.com
Go to Question: