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Question
A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is reduced to half?
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Solution
Rate of reaction, R = k [A]2
If the concentration of the reactant is reduced to half:
If [A] = `1/2` A,
rate = `k (A/2)^2`
= `1/4` kA2
Change in rate of reaction = `(1/4 kA^2) : kA^2`
= `1/4 : 1`
∴ The reaction rate decreases to one-fourth its original value.
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