Question 22 of 37beginner🔧 ApplyNumerical3 marks

Calculate the half-life of a first order reaction from their rate constants given below: (i) 200 s−1200 \text{ s}^{-1} (ii) 2 min−12 \text{ min}^{-1} (iii) 4 years−14 \text{ years}^{-1}

(i)
Answer

3.465×103.465 \times 10⁻³ s

(ii)
Answer

0.3465 min

(iii)
Answer

0.173 years

Explanation

For a first order reaction, the half-life is related to the rate constant by the formula t₁/₂ = 0.693/k. This relationship shows that half-life is independent of the initial concentration of the reactant. The constant 0.693 comes from ln(2), and the units of half-life are the reciprocal of the units of k.

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