Which compound decolorizes aqueous bromine and gives white fumes of $HCl$ on reaction with $PCl_5$?

Compound $(P)$ is

Alcohols react with Grignard reagent to form

Which one of the following is a secondary alcohol?

$A$ hydroxy compound $(X)$ with molar mass $122 \ g \ mol^{-1}$ is acetylated with acetic anhydride,using a large excess of the reagent ensuring complete acetylation of all hydroxyl groups. The product obtained has a molar mass of $290 \ g \ mol^{-1}$. The number of hydroxyl groups present in compound $(X)$ is :

Identify $P_3$ in the following reaction sequence: