What is the product of the following reaction?

Consider the following reactions:
$X + HCl \xrightarrow{\text{Anhydrous } AlCl_3} C_2H_5Cl$ (Addition)
$Y \xrightarrow{\text{Anhydrous } ZnCl_2 / HCl} C_2H_5Cl$ (Substitution)
$Y$ can be converted to $X$ on heating with $...$ at $...$ temperature:

Write the mechanism of hydration of ethene to yield ethanol.

$A$ compound $X$ absorbs $2$ moles of hydrogen and $X$ upon oxidation with $KMnO_4 \mid H^{+}$ gives the products shown below:
$CH_3-CO-CH_3$,$CH_3-COOH$ and $CH_3-CO-CH_2-CH_2-COOH$.
The total number of $\sigma$ bonds present in the compound $X$ is . . . . . .

Describe the physical properties of alkenes.

The product $A$ of the following reaction is:
$R_2C=CHR' \xrightarrow[Zn/H_2O]{O_3} A$