Question

The rate constant of a reaction with a virus is $3.3\times 10{-}^{-4}{s}^{-1}$. Time required for the virus to become 75% inactivated is:

• A. 35 min
• B. 70 min
• C. 105 min
• D. 17.5 min

Answer 1

The correct option is B 70 min

As we know,
For a first order reaction,
$t_{1/2}=\frac{0.693}{k}$
= 2100 s = 35 min
so for 75 %
$t_{75\%}=2t_{1/2}=2\times 35=70min$