Concept:The order of a reaction with respect to a specific reactant is defined strictly by its exponent in the experimental rate law.
Formula:$$ \text{Rate} = k[\text{A}]^{2}[\text{B}] $$
Solution:- The question asks for the order specifically with respect to 'A'.
- Looking at the given rate law, the concentration of A is raised to the power of 2.
- Therefore, regardless of what happens to B, the reaction is strictly 2nd order with respect to A.
- (Note: Because B is in excess, its concentration remains effectively constant, making the overall order pseudo-2nd order, but the order specifically w.r.t A remains 2).
Why other options are incorrect:The exponent for A is 2, not 1 or 3. Pseudo-first order would occur if A's exponent was 1 and B was in excess.
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