Question
A reaction is first order in A and second order in B
(i) Write differential rate equation.
(ii) How is the rate affected when the concentration of B three times?
(iii) How is the rate affected when the concentrations of both A and B are doubled?
Solution
(i) Differential rate equation of reaction is
(ii) When conc. of B is tripled, it means conc. of B becomes [3 x B]
∴ New rate of reaction,
i.e., rate of reaction will become 9 times.
(iii) When conc. of A is doubled and that of B is also doubled, then conc. of A becomes [2A] and that of B becomes [2B] rate of reaction
i.e., the rate of reaction will become 8 times the rate as in (1).
(ii) When conc. of B is tripled, it means conc. of B becomes [3 x B]
∴ New rate of reaction,
i.e., rate of reaction will become 9 times.
(iii) When conc. of A is doubled and that of B is also doubled, then conc. of A becomes [2A] and that of B becomes [2B] rate of reaction
i.e., the rate of reaction will become 8 times the rate as in (1).
