Methanol and ethanol are distinguished by the

The adduct of the compound $'A'$ obtained by the reaction with excess of isopropyl magnesium iodide,upon hydrolysis gives a tertiary alcohol. The compound $'A'$ is

$X + HCl$ $\xrightarrow[\text{Addition}]{\text{Anhy. } AlCl_3} C_2H_5Cl \xleftarrow[\text{Substitution}]{\text{Anhy. } ZnCl_2/HCl} Y$. The conversion of $Y$ to $X$ can be achieved by heating with .......... at .......... temperature.

An aromatic compound $A$ of the molecular formula $C_8H_{10}O$ on reaction with iodine and dilute $NaOH$ gives a yellow precipitate. The structure of the compound is expected to be

Compound $(P)$ is

Alcohols react with active metals,e.g.,$Na, K$ etc. to give corresponding alkoxides. Write down the decreasing order of reactivity of sodium metal with primary,secondary and tertiary alcohols.