Predict the nature of $P$ in the following reaction:
$CH_3-C\equiv C-CH_3 \xrightarrow[heat]{NaNH_2 / \text{inert solvent}} P$

Which of the following is suitable for the preparation of alkene from alkyne?

The major products $P$ and $Q$ in the following reactions,respectively,are:
$H_3C-C \equiv C-CH_2CH_3 \xrightarrow{H_2, \text{Lindlar's Catalyst}} P$
$H_3C-C \equiv C-CH_2CH_3 \xrightarrow{Na/\text{liquid } NH_3} Q$

Predict the product $C$ obtained in the following reaction of but$-1-$yne: $CH_3-CH_2-C \equiv CH + HCl \to B \xrightarrow{HCl} C$

The major product of the following reaction is:

Which of the following reagents is used to distinguish propene and propyne?