$CaC_2 + 2D_2O \longrightarrow$ "$P$" $+ Ca(OD)_2$
In the above reaction,the product "$P$" is:

Which alkyne will give $3$-ethylhexane on catalytic hydrogenation?

Consider the following reaction sequence:
$CH_3CH_2CH_2CH(Br)CH_2Br + 2NaNH_2 \rightarrow X$
$X \xrightarrow[(ii) (CH_3)_2CHBr]{(i) NaNH_2} Y$
The product $Y$ formed is:

Which of these will not react with acetylene?

Which of the following reactions forms an aldehyde as a product?

Hex$-1-$yne on reaction with $Br_2$ (excess)/ $CCl_4$,gives