Question

The kinetic of the reaction 2N₂O₅ ⇾ 4 NO₂ + O₂ in liquid bromine medium was measured independently for the three different initial concentrations of N₂O: 0.11,0.07 and 0.05 mol L^{-1 .}The half - life of the reaction was found to be 4.5 hours for all these concentrations. The order of the reaction is

• A. 0.5
• B. 1
• C. 0
• D. 2

Answer 1

The Correct Option is B

To determine the order of the reaction, we can use the information about the half-life. The half-life of a reaction depends on its order:

• Zero order: Half-life \(t_{1/2} = \frac{[A]_0}{2k}\)
• First order: Half-life \(t_{1/2} = \frac{\ln 2}{k}\)
• Second order: Half-life \(t_{1/2} = \frac{1}{k[A]_0}\)

Given that the half-life is constant at 4.5 hours for different initial concentrations, this indicates that the half-life does not depend on \([A]_0\). In the case of a first-order reaction, the half-life is independent of the initial concentration, as shown by \(t_{1/2} = \frac{\ln 2}{k}\). Therefore, the reaction follows a first-order kinetics.

Thus, the order of the reaction is 1.