Increasing order of boiling points in the following compounds is:
$I$. $CH_3COOH$
$II$. $CH_3CH_2CHO$
$III$. $CH_3CH_2CH_2OH$
$IV$. $CH_3COCH_3$

Product $(A)$ and $(B)$ respectively in the above reaction are

Ethyl ester $\xrightarrow{CH_3MgBr \text{ (excess)}} P$. The product $P$ will be

Ethanol $(C_2H_5OH)$ and formic acid $(HCO_2H)$ cannot be distinguished by:

Compound $A$ was prepared by oxidation of compound $B$ with alkaline $KMnO_4$. Compound $A$ on reduction with lithium aluminium hydride $(LiAlH_4)$ gets converted back to compound $B$. When compound $A$ is heated with compound $B$ in the presence of $H_2SO_4$,it produces a fruity smell of compound $C$. To which family do the compounds $A$,$B$,and $C$ belong?

Assertion : The $pK_a$ of acetic acid is lower than that of phenol.
Reason : Phenoxide ion is more resonance stabilised.