Question

The half-life period if the first order chemical reaction is 6.93 min. The time required for the completion of 99% of the chemical reaction will be (log2 = 0.3010):

• A. 230.3 min
• B. 23.03 min
• C. 46.06 min
• D. 460.6 min

Answer 1

The correct option is C 46.06 min

The half life period $t_{1/2}=6.93$ min.

The decay constant $\lambda =\frac{0.693}{t_{1/2}}=\frac{0.693}{6.93min}=0.1/min$

$t=\frac{2.303}{\lambda }log\frac{a}{a-x}$

$t=\frac{2.303}{0.1/min}log\frac{100}{100-99}$

$t=46.06min$

Hence, the time required for 99% completion of the reaction is 46.06 min