Acetylene when passed through red hot iron tube at 873 K , undergoes cyclic polymerisation benzene which upon subsequent nitration gives nitrobenzene.

In presence of organic peroxides, the addition of HBr to propene follows anti Markowinkov's rule (or peroxide effect) to form 1-bromopropane ( $n$-propyl bromide)

However, in absence of peroxides, addition of HBr to propene follows Markownikoff's rule and gives 2 - bromopropane as major product.

Electrophiles are electron deficient species. They may be natural or positively charged e.g., (iii) $\mathrm{C}_{\mathrm{l}}$, (iv) $\mathrm{Cl}_2 \mathrm{C}$, (v) $\left(\mathrm{H}_3 \mathrm{C}_3 \mathrm{C}^{+}\right.$

Nucleophiles are electron rich species. They may be neutral or negatively charged e.g.,

(i) H$_3$CO$^-$,

(ii)

(vi) Br$^-$, (vii) $${H_3}C - \mathop O\limits_{ \bullet \, \bullet }^{ \bullet \, \bullet } - H$$

(viii) $$R\mathop N\limits^{ \bullet \bullet } HR$$

The given organic compound is

This compound has 9 primary hydrogen, 2 secondary and one tertiary hydrogen atoms. The relative reactivity of $1^{\circ}, 2^{\circ}$ and $3^{\circ}$ hydrogen atoms towards chlorination is $1: 3.8: 5$. Relative amount of product after chlorination $=$ Number of hydrogen $\times$ relative reactivity

$$ \begin{array}{llll} \text { Relative } & 1^{\circ} \text { halide } & 2^{\circ} \text { halide } & 3^{\circ} \text { halide } \\ \text { amount } & 9 \times 1=9 & 2 \times 38=7.6 & 1 \times 5=5 \end{array} $$

Total amount of mono chloro product $=9+7.6+5=21.6$

Percentage of $1^{\circ}$ mono chloro product $=\frac{9}{21.6} \times 100=41.7 \%$

Percentage of $2^{\circ}$ mono chloro product $=\frac{7.6}{21.6} \times 100=35.2 \%$

Percentage of $3^{\circ}$ mono chloro product $=\frac{5}{21.6} \times 100=23.1 \%$.