Polymerisation product of propyne is

The correct sequence of reagents for the following conversion will be

The major product of the following reaction is

The major product in the following reactions is

${\mathrm{C}}_6{\mathrm{H}}_5-\mathrm{C}\equiv \mathrm{CH}\underset{\left(\mathrm{ii}\right)\mathrm{HI}\left(1\mathrm{eq}\right)}{\overset{\left(\mathrm{i}\right)\mathrm{HCl}\left(1\mathrm{eq}\right)}{\to }}$

In the reaction


$\mathrm{x}$ and $\mathrm{y}$ , respectively, are

In the compound, 

$\underset{\left(\mathrm{I}\right)}{{\mathrm{CH}}_2}=\underset{\left(\mathrm{II}\right)}{\mathrm{CH}}-\mathrm{C}\underset{\left(\mathrm{III}\right)}{\equiv \mathrm{CH}}$

The most acidic hydrogen atom is

Which among the following depicts the correct order of acidity?