CBSE Class 12 · 2010 · Delhi · Chemical KineticsShort Answer

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A reaction is of first order in reactant A and of second order in reactant B. How is the rate of this reaction affected when (i) the concentration of B alone is increased to three times, (ii) the concentrations of A as well as B are doubled?

Answer: (i) Rate ×9. (ii) Rate ×8.

Solution

Rate

= k [A] [B]^{2}

.
(i)

[B] \to 3 [B]

rate \to k [A] (3 [B])^{2} = 9 k [A] [B]^{2} — nine times

(ii) both doubled:

rate \to k (2 [A]) (2 [B])^{2} = 8 k [A] [B]^{2} — eight times

CBSE Class 12 Board · 2010 · Delhi · Subjective

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