Question

Half-life period is independent of the concentration for

• A. Zero order reaction
• B. First order reaction
• C. Second order reaction
• D. Any type of reaction

Hint:

Half-life for first order reaction: \(t_{1/2} = 0.693/k\).
Independent of initial concentration.
Radioactive decay is a first order process.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Half-life (\(t_{1/2}\)) is the time required for the concentration of a reactant to decrease to half of its initial value.

Step 2: Detailed Explanation:
For different orders of reaction:
- Zero order: \(t_{1/2} = \frac{[A]_0}{2k}\) (depends on initial concentration).
- First order: \(t_{1/2} = \frac{0.693}{k}\) (independent of initial concentration).
- Second order: \(t_{1/2} = \frac{1}{k[A]_0}\) (depends on initial concentration).
Thus, for first order reactions, the half-life is independent of concentration.

Step 3: Final Answer:
Thus, the half-life is independent of concentration for first order reactions.
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