Question

The decomposition of AB\(_3\)(g) is a zero order reaction. At 300 K, the rate constant of the reaction is \(2.5 \times 10^{-4}\) mol L\(^{-1}\) s\(^{-1}\). What is the rate of reaction (in mol L\(^{-1}\) s\(^{-1}\)) when the concentration of AB\(_3\)(g) is taken as 10\(^{-1}\) mol L\(^{-1}\) at 300 K?

• A. \(2.5 \times 10^{-5}\)
• B. \(2.5 \times 10^{-4}\)
• C. \(2.5 \times 10^{-3}\)
• D. \(5 \times 10^{-4}\)

Hint:

Remember that for a zero-order reaction, the rate is constant and independent of reactant concentration. The rate = k.

Answer 1

The Correct Option is B

Step 1: Understand Zero-Order Reactions.
For a zero-order reaction, the rate of the reaction is independent of the concentration of the reactants. The rate law for a zero-order reaction is given by: \[ \text{Rate} = k[\text{Reactant}]^0 = k \] where \(k\) is the rate constant. Step 2: Apply the given information.
The problem states that the decomposition of AB\(_3\)(g) is a zero-order reaction. The rate constant, \(k\), at 300 K is given as \(2.5 \times 10^{-4}\) mol L\(^{-1}\) s\(^{-1}\).
Since the reaction is zero-order, the rate of the reaction is equal to the rate constant, regardless of the concentration of AB\(_3\). Step 3: Determine the rate of reaction.
The rate of the reaction is equal to the rate constant \(k\), which is \(2.5 \times 10^{-4}\) mol L\(^{-1}\) s\(^{-1}\). The concentration of AB\(_3\) is irrelevant for a zero-order reaction. Step 4: Match the rate with the options.
The rate of the reaction is \(2.5 \times 10^{-4}\) mol L\(^{-1}\) s\(^{-1}\), which corresponds to option (2).