Which product is obtained from the reaction of calcium carbide with water?

Identify the alkyne in the following sequence of reactions:

Predict the product of the following reaction sequence:
$HC \equiv CH$ $\xrightarrow[\begin{smallmatrix} (2) \text{ excess } I-CH_2-(CH_2)_2-CH_3 \\ (3) \text{ } H^{\oplus} \end{smallmatrix}]{(1) \text{ excess } NaNH_2}$

Which of the following reagents is most suitable to distinguish compound $(3)$ from the others?
$(1) \ CH_3-C \equiv C-CH_3$
$(2) \ CH_3CH_2CH_2CH_3$
$(3) \ CH_3CH_2C \equiv CH$
$(4) \ CH_3CH=CH_2$

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

When $23 \ g$ of $Na$ reacts with $1 \ mole$ of propyne,how many moles of $H_2$ gas will be released?