Question

In a reaction \( A \to \) Products, when start is made from \( 8.0 \times 10^{-2} \) M of A, half-life is found to be 120 minutes. For the initial concentration \( 4.0 \times 10^{-2} \) M, the half-life of the reaction becomes 240 minutes. The order of the reaction is:

• A. zero
• B. one
• C. two
• D. 0.5

Hint:

For a second-order reaction, the half-life is inversely proportional to the concentration of the reactant.

Answer 1

The Correct Option is C

The relationship between half-life (\( t_{1/2} \)) and concentration for different orders of reactions can be used to determine the order. The fact that the half-life doubles when the concentration is halved indicates that the reaction follows second-order kinetics. Therefore, the order of the reaction is 2.
Step 2: Conclusion.
The correct answer is (C), two.