Which of the following hydrocarbons forms a salt?

The reaction $R-C \equiv C-R \xrightarrow{H_2 / \text{Lindlar's catalyst}}$ gives the major product as ..............

Explain: 'Hydrogen attached to a carbon having a triple bond is acidic in nature.' Also,write an appropriate reaction for it.

The reagents to carry out the following conversion are:

In the following reaction sequence: $Ph-CH=CH-Ph$ $\xrightarrow{Br_2/CCl_4} (A)$ $\xrightarrow{2NaNH_2} (B)$ $\xrightarrow{H_2/Pd-CaCO_3} (C)$,the product $(C)$ is:

Which of the following reactions will yield $2, 2-$dibromopropane?