The number of $\sigma$ and $\pi$ bonds present in $pent-4-en-1-yne$ is

Acetylene gas when passed through $20\% \ H_2SO_4$ at $80 \, ^\circ C$ gives acetaldehyde. The catalyst required for this conversion is:

Identify the reagent used for the following conversion: $CH_3-C \equiv C-CH_3 \longrightarrow \text{cis-but-2-ene}$

Which of the following compounds produces hydrogen gas upon reaction with sodium?

In the reaction $CaC_2 + H_2O \to A \xrightarrow{H_2SO_4/HgSO_4} B$,what are $A$ and $B$?

Ethyne on reaction with dil. $H_2SO_4$ and $Hg(II)$ gives: