Hydrocarbons — Chemistry STD 11 Science — Question

3. Three

Explanation:

In the first step, one mole NaNH_2​ is the base in an elimination reaction to give the alkenyl bromide.

In the second reaction, likewise a second equivalent of NaNH₂​ performs a second elimination reaction to form the alkyne.

For a terminal alkyne, any excess NaNH₂​ will remove the acidic hydrogen from terminal C−H and give the alkynyl anion.

So if a terminal alkyne is formed, three equivalents of NaNH₂​ will be consumed; the alkyne is protonated upon workup, usually by adding water.