Which of the following gives $H_2$ gas with $Na$?

Schemes $1$ and $2$ describe the sequential transformation of alkynes $M$ and $N$. Consider only the major products formed in each step for both the schemes.
$1.$ The product $X$ is:
$2.$ The correct statement with respect to product $Y$ is:
$(A)$ It gives a positive Tollens test and is a functional isomer of $X$.
$(B)$ It gives a positive Tollens test and is a geometrical isomer of $X$.
$(C)$ It gives a positive iodoform test and is a functional isomer of $X$.
$(D)$ It gives a positive iodoform test and is a geometrical isomer of $X$.

$A$ compound is treated with $NaNH_2$ to give a sodium salt. Identify the compound.

Which one is the correct order of acidity?

When calcium carbide is reacted with heavy water,which of the following product$(s)$ will be formed?
$I$. $CD_4$
$II$. $C_2D_2$
$III$. $Ca(OD)_2$
$IV$. $Ca_2 \cdot D_2O$

$Be_2C + H_2O \rightarrow Be(OH)_2 + X$
$CaC_2 + H_2O \rightarrow Ca(OH)_2 + Y$
Then $X$ and $Y$ are respectively: