The reagent used in preparation method of alkynes from geminal dihalides is 

For the above reaction sequence, $\mathrm{R}$ and $\mathrm{P}$ are

What is the final major product of the following reaction?

In the following reaction sequence



X and Y are, respectively

The major product of the following reaction is

For the given reaction:

What is $\mathrm{A}$?

${\mathrm{CaCO}}_3\left(\mathrm{s}\right)\stackrel{\mathrm{Heat}}{\to }\mathrm{ }\mathrm{X}\left(\mathrm{s}\right)+\mathrm{Z}\left(\mathrm{g}\right)$

$\mathrm{X}\left(\mathrm{s}\right)\stackrel{\mathrm{Carbon}, \mathrm{heat}}{\to }\mathrm{ }\mathrm{C}\left(\mathrm{s}\right)+\mathrm{D}\left(\mathrm{g}\right)$

$\mathrm{C}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\to \mathrm{E}\left(\mathrm{g}\right).$

What is E and C respectively ?

The reagent(s) for the following conversion,

$\mathrm{Br}-{\mathrm{CH}}_2-{\mathrm{CH}}_2-\mathrm{Br} \stackrel{?}{\to } \mathrm{CH}\equiv \mathrm{CH}$

is/are