Predict the product $B$ in the sequence of reaction:
$HC \equiv CH$ $\xrightarrow{30\% \ H_2SO_4, HgSO_4} A$ $\xrightarrow{dil. \ NaOH} B$

Match the following reactions in List-$I$ with their products in List-$II$.

List-$I$ (Reaction)	List-$II$ (Product)
$A$. $\text{Ketone} + NaBH_4$	$I$. $1^\circ$-alcohol
$B$. $\text{Ester} + LiAlH_4$	$II$. $3^\circ$-alcohol
$C$. $RMgX + \text{Ketone}$	$III$. $2^\circ$-alcohol
	$IV$. $\text{Alkane}$

What is the correct order of reactivity of the following compounds towards a Grignard reagent?
$(I)$ $CH_3CHO$
$(II)$ $HCHO$
$(III)$ $CH_3COC_6H_5$

An organic compound $(X)$ with molecular formula $C_3H_6O$ is not readily oxidised. On reduction it gives $(C_3H_8O)$ $(Y)$ which reacts with $HBr$ to give a bromide $(Z)$ which is converted to a Grignard reagent. This Grignard reagent on reaction with $(X)$ followed by hydrolysis gives $2,3-$dimethylbutan$-2-$ol. Compounds $(X)$,$(Y)$ and $(Z)$ respectively are $:$

Which of the following compounds forms lactic acid upon the formation of its cyanohydrin followed by hydrolysis?

Reaction of ethyl formate with excess of $CH_3MgI$ followed by hydrolysis gives