In the following reaction sequence,$X$ and $Y$,respectively,are:
$CH_2=C(CH_3)_2$ $\xrightarrow{X} \text{Epoxide}$ $\xrightarrow{Y} (CH_3)_3C-OH$

Iodoform can be obtained on warming $NaOH$ and iodine with

$A$ 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 :

$HO-CH_2CH_2CH_2CH_2-Br \xrightarrow{KOH} \text{Product}$. The product is:

Identify $P_3$ in the following reaction sequence:

$A$ compound $A$ on oxidation gives acetaldehyde,and further oxidation gives an acid. After the first oxidation,the product reacts with ammoniacal $AgNO_3$ to produce a silver mirror. Compound $A$ is likely to be: