Carbon halogen bond is a polar bond as halogens are more electro negative than carbon. The carbon atom exhibits a partial positive charge (\(\delta \)+) and halogen atom a partial negative charge (\(\delta \)-)
The C -X bond is formed by overlap of sp³ orbital of carbon atom I with half filled p-orbitat of the halogen atom. The atomic size of halogen increases from fluorine to iodine, which increases the C - X bond length. Larger the size, greater is the bond length, and weaker is the bond formed. The bond strength of C - X decreases from C - F to C - I in CH₃X

The Chlorination of methane is carried out by free radical mechanism. The initiation step to form free radical needs high energy which is supplied by light energy.
\(\mathrm{Cl}-\mathrm{Cl} \stackrel{h \nu}{\longrightarrow} 2 \mathrm{Cl}\)
So this reaction is not possible in dark.

Chloroform undergoes oxidation in the presence of light and air to form phosgene (carbonyl chloride)

Since phosgene is very poisonous, its presence makes chloroform unfit for use as anaesthetic.

With acetyl chloride, CH₃MgI given first acetone.

The acetone formed will react with excess CH₃MgI to give a tertiary alcohol, t - butyl alcohol.

i) chiral molecule:
The chiral molecule is
ii) S_N2 reaction:
undergoes S_N2 reaction faster as it is a primary alkyl halide.
\( \text { (or) } \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{Cl}\\ 1 - chlorobutane\)