The half life of a radioactive element is $$20\,\min .$$ The time interval between the stages of its $$33\% $$ and $$67\% $$ decay is
A.
$$40\,\min $$
B.
$$20\,\min $$
C.
$$30\,\min $$
D.
$$25\,\min $$
Answer :
$$20\,\min $$
Solution :
Change in 67% to 33% is almost half the concentration change.
\[67\% \xrightarrow[{{\text{change}}}]{{{\text{Half}}}}33.5\left( { \approx 33\% } \right)\]
So time interval between the stages of its 33% and 67% decay is same as $${t_{\frac{1}{2}}} = 20\,\min .$$
Releted MCQ Question on Physical Chemistry >> Chemical Kinetics
Releted Question 1
If uranium (mass number 238 and atomic number 92) emits an $$\alpha $$ -particle, the product has mass no. and atomic no.