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STD 12 - 3. Chemical kinetics — NEET STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceNEETSTD 12 - 3. Chemical kinetics4 Marks
MCQ
A molecule undergoes two independent first order reactions whose respective half lives are $12\,min$ and $3\,min$. If both the reactions are occurring then the time taken for the $50 \%$ consumption of the reactant is $..........\,\min$ (Nearest integer)
  • A
    $4$
  • ✓
    $2$
  • C
    $6$
  • D
    $8$
✓

Answer

Correct option: B.
$2$
b
$\frac{1}{t_{1 / 2}}=\frac{1}{3}+\frac{1}{12}=\frac{4+1}{12}=\frac{5}{12}$

$t_{1 / 2}=\frac{12}{5} min =2.4$

$\approx 2$

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