Which is the most reactive hydrocarbon among the following?

In the given reaction,
$Ph-C \equiv C-CH_3 \xrightarrow{H^{+}/Hg^{2+}} A$
the product $A$ is

Which one of the following statements is false?

Which of the following compounds forms a $Na$-salt upon reaction with $NaNH_2$?

Acetylene reacts with dilute $H_2SO_4$ in the presence of $HgSO_4$ to produce .......

When propyne is passed through a red hot iron tube at $873 \ K$,the reaction gives a product having the molecular formula of: