Unit of k in first order reaction is:
Correct answer: A. s-1
- A. s-1
- B. mol dm-3 s-1
- C. mol dm-3
- D. mol-1 dm3
Explanation
In a first-order reaction, the rate constant k is derived from the formula: k = rate / [A], where [A] is the concentration of a reactant. The unit for rate is mol L-1 s-1 and the unit for concentration is mol L-1. By dividing these units, the concentration units cancel out, leaving the unit for k as s-1. Therefore, the correct answer is option A.Option B is incorrect because it represents the unit of the reaction rate, not the rate constant for a first-order reaction. Option C is incorrect because it represents concentration. Option D is incorrect because it might be appropriate for a second-order reaction, but not for a first-order reaction.
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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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