The above reaction is an example of Chlorination. Chlorination is the substitution of hydrogen atoms by chlorine atom.
The conditions used in the above process is $U.V.$ light or diffused sunlight or $400^{\circ} C$.
This reaction is an example of substitution reaction.

$\begin{array}{*{20}{c}}
{C{H_3} - C = CH - C{H_2}C{H_3}} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{CH{{(C{H_3})}_2}\,\,\,\,\,\,\,\,\,\,}
\end{array}\xrightarrow[{(ii)\,{H_2}{O_2},O{H^ - }}]{{(i)\,{B_2}{H_6}}}[A]$$\xrightarrow[\Delta ]{{dil.\,{H_2}S{O_4}}}[B]$

$\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,C{H_3}} \\
|
\end{array}} \\
{C{H_3} - C - C{H_3}} \\
| \\
H
\end{array}{\mkern 1mu} $ $\mathop {\xrightarrow{{C{H_3}OBr}}}\limits_{C{H_3}OH} $

$C{H_3} - C \equiv C - H\xrightarrow{{NaN{H_2}}}\xrightarrow{{C{H_3} - I}}(A)\xrightarrow{{Li/liq\,N{H_2}}}(B)$
$C{H_3} - C \equiv C - H\xrightarrow{{NaN{H_2}}}\xrightarrow{{C{H_3} - I}}(A)\xrightarrow[{Pd.CaC{O_3}}]{{{H_2}}}(C)$
પ્રક્રિયામાં શ્રેણી ને ધ્યાનમાં રાખતા પદાર્થ $C$ શું હશે?3