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Which statement about the half-life of reactions is correct?
AHalf-life of a first order reaction depends on initial concentration
BHalf-life of a zero order reaction is independent of initial concentration
CHalf-life of a first order reaction is independent of initial concentration
DHalf-life of a zero order reaction is inversely proportional to k squared
Answer & Solution
Correct answer: C. Half-life of a first order reaction is independent of initial concentration
1. For first order, $t_{1/2} = \dfrac{0.693}{k}$, with no concentration term.
2. So first order half-life is independent of $[R]_0$.
3. For zero order, $t_{1/2} = \dfrac{[R]_0}{2k}$, so it does depend on $[R]_0$.
4. Hence option C is correct and option B is the reverse of the truth.
_Source: NCERT Class 12 Chemistry Ch 3 "Chemical Kinetics", p.16_
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