Question

The half life period of a first order chemical reaction is 6.93 minutes. Time required for the completion of 99% of the chemical reaction will be (log 2 = 0.301) :

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

Answer 1

Answer: (B)

46.06 minutes

Answer 2

In first order reaction for X% complation

$\frac{0.693}{t_{1/2}} = \frac{2.303}{t}\log\left( \frac{100}{100 - 90} \right)$

$= \frac{0.693}{6.93} = \frac{2.303 \times 2}{t}$

So, t = 46.06 min.