Question

What is the unit of rate constant for the zero-order reaction?

• A. mol dm\(^{-3}\)t\(^{-1}\)
• B. mol dm\(^3\)t\(^{-1}\)
• C. t\(^{-1}\)
• D. mol dm\(^{-3}\)t

Hint:

For zero-order reactions, the rate constant has the units of mol dm\(^{-3}\)t\(^{-1}\), as the rate is independent of concentration.

Answer 1

The Correct Option is A

Step 1: Understanding zero-order reaction.
In a zero-order reaction, the rate of reaction is independent of the concentration of reactants. The rate law for a zero-order reaction is: \[ \text{Rate} = k \] Where \(k\) is the rate constant, and the rate is independent of the concentration of reactants. The unit of the rate is mol dm\(^{-3}\)t\(^{-1}\). Therefore, the unit of the rate constant for a zero-order reaction is also mol dm\(^{-3}\)t\(^{-1}\).
Step 2: Analyzing the options.
(A) mol dm\(^{-3}\)t\(^{-1}\): This is correct. The unit of rate constant for a zero-order reaction is mol dm\(^{-3}\)t\(^{-1}\).
(B) mol dm\(^3\)t\(^{-1}\): This is incorrect. The unit for a zero-order reaction is mol dm\(^{-3}\), not mol dm\(^3\).
(C) t\(^{-1}\): This is incorrect. This unit corresponds to the first-order reaction rate constant.
(D) mol dm\(^{-3}\)t: This is incorrect. The correct unit should be mol dm\(^{-3}\)t\(^{-1}\), not mol dm\(^{-3}\)t.
Step 3: Conclusion.
The correct answer is (A) mol dm\(^{-3}\)t\(^{-1}\).