JEE Advanced · 2007 · 08 Apr 2007 · Paper 2 · Chemical Kinetics

Consider a reaction

aG + bH \to

Products. When concentration of both the reactants G and H is doubled, the rate increases by eight times. However, when concentration of G is doubled keeping the concentration of H fixed, the rate is doubled. The overall order of the reaction is

(A)0
(B)1
(C)2
(D)3✓ Correct

Answer: (D)

Solution

Let the rate law be: rate

= k [G]^{m} [H]^{n}

. When both [G] and [H] are doubled:

(2)^{m} \times (2)^{n} = 8 = 2^{3}

, so

m + n = 3

. When only [G] is doubled:

(2)^{m} = 2

, so

m = 1

. Therefore

n = 3 - 1 = 2

. The overall order is

m + n = 1 + 2 = 3

JEE Advanced · 2007 · 08 Apr 2007 · Paper 2 · Single correct option

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