For a hypothetical reaction: x2 + y2 → 2xy, the proposed mechanism is: (i) x2 → x + x (Fast) (ii) x + y2 → xy + y (slow) (iii) x + y → xy (Fast) The order of reaction will be:
Correct answer: D. 2
- A. 0
- B. 1
- C. 1.5
- D. 2
Explanation
The overall rate of a reaction is determined by the slowest step in the mechanism, which is often referred to as the rate-determining step.In this proposed mechanism, step (ii) is the slow step. The rate law for this step would be:Rate = k × [x] × [y2]This indicates that the rate of the reaction depends on the concentrations of both x and y, raised to the power of 1 for each, making it a first-order reaction with respect to both x and y.Since the reaction is first-order with respect to both x and y, the overall reaction order is the sum of the individual reaction orders, which gives us a total reaction order of 1 + 1 = 2.So, option D, "2," is the correct choice.
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Reaction kinetics relates reaction rate to concentration, temperature, surface area and catalysts. Questions cover rate laws, reaction order, rate constants, activation energy and the activated complex, including how a catalyst lowers the activation energy without changing the overall energy change or equilibrium position.
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