Chemistry · Reaction Kinetics
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Consider the following.general reaction lA .. lB → Products rate of this reaction is expressed as
Rate = K[A][B]' the correct order of reaction and molecularity is:
- A
2:2
- B
2:3
- C
3:2
- D
3:3
The correct answer is 2:2. The order of a reaction is determined by the sum of the exponents of the concentration terms in its rate law. In this case, Rate = K[A][B] implies an order of 1 with respect to A and 1 with respect to B, giving an overall order of 2. Molecularity refers to the number of reactant molecules involved in an elementary reaction step. Since the reaction involves two molecules (A and B), the molecularity is 2. Other options are incorrect because they either misrepresent the number of reactant molecules involved or miscalculate the reaction order.
This is correct because the reaction order is the sum of the powers of the concentration terms in the rate equation, which is 1+1=2. Molecularity, based on the number of molecules involved in the rate-determining step, is also 2.
This option is incorrect because the molecularity cannot be 3 when there are only two reactant molecules involved in the elementary step.
This option is incorrect because it suggests a reaction order of 3, which does not match the given rate law expression where the order is 1+1=2.
This option is incorrect because neither the molecularity nor the reaction order is 3 in this context.
Tagged under Chemistry · Reaction Kinetics · 2008