question_answer

The time taken for 90% of a first order reaction to complete is approximately

A) 1.1 times that of half-life

B) 2.2 times that of half-life

C) 3.3 times that of half-life

D) 4.4 times that of half-life

Correct Answer: C

Solution :

[c]  \[{{t}_{90}}\]% \[=\frac{2.303}{k}\log \frac{100}{100-50}\,\,\,\,\,\,(I)\]   \[{{t}_{50}}\]%  \[=\frac{2.303}{k}\log \frac{100}{100-50}\,\,(II)\]      \[\therefore {{t}_{90}}\]% \[=3.3\,{{t}_{50}}\]%