Statement I: If in a zero-order reaction, the concentration of the reactant is doubled, the half-life period is also doubled
Statement II: For a zero-order reaction, the rate of reaction is independent of the initial concentration
Answer & explanation
Correct answer: option 2
The correct answer is option 2. Statement I and statement II are correct but statement II is not the correct explanation of statement I.
Statement 1
For a zero-order reaction, the relationship between the half-life period ($t_{1/2}$) and the initial concentration ($[R]_0$) is given by the formula:
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Conclusion: Since $t_{1/2}$ is directly proportional to the initial concentration ($t_{1/2} \propto [R]_0$), if the concentration of the reactant is doubled, the half-life period will also be doubled.
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Statement I is CORRECT.
Statement II
The rate law for a zero-order reaction is expressed as:
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Conclusion: This shows that the rate of reaction remains constant and is independent of the concentration of the reactants at any given time, including the initial concentration.
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Statement II is CORRECT.
So,
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Statement I is about the time required for half the reactant to be consumed ($t_{1/2}$).
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Statement II is about the speed of the reaction ($Rate$).
While both statements are factually true for zero-order reactions, Statement II is not the reason why Statement I is true. Statement I is a direct consequence of the integrated rate equation for zero order, whereas Statement II describes the nature of the rate itself.
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Correct Option: Option 2 (Both statements are correct, but Statement II is not the correct explanation of Statement I).