MCQ
For a first order reaction velocity constant, $K = {10^{ - 3}}{s^{ - 1}}$. Two third life for it would be ........... $\sec$
- A$3300 $
- B$2200$
- ✓$1100$
- D$4400 $
✓
Answer
Correct option: C.
$1100$
c
(c)We know that $k = \frac{{2.303}}{t}\log \frac{a}{{a - x}}$
(c)We know that $k = \frac{{2.303}}{t}\log \frac{a}{{a - x}}$
${10^{ - 3}} = \frac{{2.303}}{t}\log \frac{a}{{(a - \frac{{2a}}{3})}}$,
${10^{ - 3}} = \frac{{2.303}}{t}\log \,3$
${10^{ - 3}} = \frac{{2.303}}{t} \times 0.4771,$
$t = \frac{{2.303 \times 0.4771}}{{{{10}^{ - 3}}}}$
$ =1100\,\sec $
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