The compound $X$ on reaction with $HgSO_4 + H_2SO_4$ gives $Y$ which on oxidation gives acetic acid. $X$ is

The gaseous mixture used for welding of metals is

In which of the following molecules,$2$ $\pi$ bonds are present?

$A$ $\xrightarrow[1\% \ HgSO_4]{20\% \ H_2SO_4} B$ $\xrightarrow{I_2 + NaOH} C + C_6H_5COONa$. The reactant $A$ is

The electrolysis of aqueous potassium maleate gives which of the following products?

Product $(C)$ is: $Ph-CH=CH_2$ $\xrightarrow[CCl_4]{Br_2} (A)$ $\xrightarrow[(ii) NaNH_2]{(i) alc. KOH} (B)$ $\xrightarrow[(ii) CH_3-Cl]{(i) NaNH_2} (C)$