But$-1-$yne on reaction with dil. $H_2SO_4$ in the presence of $Hg^{2+}$ ions at $333 \ K$ gives:

When $2$-butyne is treated with $Pd-BaSO_4$ (Lindlar's catalyst),the product formed will be:

Which of the following does not give a white precipitate with ammoniacal $AgNO_3$?

Given below are two statements:
Statement $I$: One mole of propyne reacts with excess of sodium to liberate half a mole of $H_2$ gas.
Statement $II$: Four $g$ of propyne reacts with $NaNH_2$ to liberate $NH_3$ gas which occupies $224 \ mL$ at $STP$.
In the light of the above statements,choose the most appropriate answer from the options given below:

Calcium carbide $+ D_2 O \longrightarrow \underline{X} + Ca(OD)_2$.
The hybridisation of carbon atom$(s)$ in $X$ is:

What is Lindlar's catalyst? Write its uses.