Question

If reactivity for chlorination with $1^{\circ }H$, $2^{\circ }H$ and $3^{\circ }H$ is $1:3.8:4.5$ respectively, what is the percentage of $\left(P2\right)$ formed:

(closest to the nearest integer of $\frac{\left(P2\right)}{10}$)

Answer 1

Relative amount of monochlorinated product=Number of hydrogens x relative reactivity.
$1°$ monochlorinated product$=1\times 3=3$
$2°$ monochlorinated product$=2\times 3.8=7.6$
$3°$ monochlorinated product$=2\times 4.5=9$
Total amount of monochlorinated compounds$=9+7.6+3$
$=19.6$
% of $2°$ monochlorinated product $P_2=\frac{7.6}{19.6}\times 100$
$=38.77$

Hence, Closest integer to $\frac{P_2}{10}=4$