When propyne is treated with dilute $H_2SO_4$ and $HgSO_4$,the major product is

Identify the compound $(Z)$ in the following reaction sequence: $CH_3-CH(Br)-CH_2Br$ $\xrightarrow{alc. KOH, \Delta}$ $\xrightarrow{NaNH_2}$ $\xrightarrow{H_2O, Hg^{2+}, H^+} (Z)$

$CH_3-C \equiv C-O-CH_3 \xrightarrow{dil. \ H_2SO_4, HgSO_4} \text{major product}$

$A$ gas decolourises bromine in $CCl_4$ and forms a precipitate with ammoniacal silver nitrate. The gas is

The reagent$(s)$ for the following conversion is/are:
$Br-CH_2-CH_2-Br \xrightarrow{?} HC \equiv CH$

Which one of the following statements is false?