In the following reaction, 

${\mathrm{CH}}_3-\mathrm{C}\equiv \mathrm{CH}\underset{873 \mathrm{K}}{\overset{\mathrm{Red} \mathrm{hot} \mathrm{iron} \mathrm{tube}}{\to }}\mathrm{A},$ the number of sigma bonds present in the product?

In the following reaction sequence



X and Y are, respectively

The major product of the following reaction is

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

The correct sequence of reagents for the following conversion will be

Which among the following depicts the correct order of acidity?