For a first-order reaction, the half-life is independent of the initial concentr

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Question: For a first-order reaction, the half-life is independent of the initial concentration. What is the expression for half-life?

Options:

Correct Answer: t1/2 = 0.693/k

Solution:

For a first-order reaction, the half-life is given by the expression t1/2 = 0.693/k.

For a first-order reaction, the half-life is independent of the initial concentration. What is the expression for half-life?

For a first-order reaction, the half-life is independent of the initial concentration. What is the expression for half-life?

Correct Answer: t1/2 = 0.693/k

Step 1: Understand what a first-order reaction is. It is a type of chemical reaction where the rate depends on the concentration of one reactant.
Step 2: Learn about half-life. Half-life is the time it takes for half of the reactant to be used up in a reaction.
Step 3: Note that for first-order reactions, the half-life does not change with different starting amounts of reactant.
Step 4: The formula for calculating the half-life (t1/2) of a first-order reaction is derived from the rate constant (k).
Step 5: The expression for half-life in a first-order reaction is t1/2 = 0.693/k.

First-Order Reactions – Reactions where the rate is directly proportional to the concentration of one reactant.
Half-Life – The time required for the concentration of a reactant to decrease to half its initial value.
Independence from Initial Concentration – In first-order reactions, the half-life does not depend on the initial concentration of the reactant.