Question

Half-life period of a first order reaction is $10$ min. What percentage of the reaction will be completed in $100$ min?

• A. $25$%
• B. $50$%
• C. $99.9$%
• D. $75$%

Answer 1

Answer: (C)

$99.9$%

Answer 2

$\frac{0.693}{t_{1/2}}$ $=\frac{2.303}{t} \,log$ $\frac{a}{a-x}$ $\frac{0.693}{10}$ $=\frac{2.303}{100}\, log$ $\frac{100}{100-x}$ $\Rightarrow$ $x=99.9\%$