In the reaction,the acid obtained will be
$CH_3CHO + HCN \to CH_3CH(OH)CN \xrightarrow{H_2O} CH_3CH(OH)COOH$

Match the reactions given in Column-$I$ with the suitable reagents given in Column-$II$.

Column-$I$ (Reactions)	Column-$II$ (Reagents)
$(A).$ Benzophenone $\to$ Diphenylmethane	$(1).$ $LiAlH_4$
$(B).$ Benzaldehyde $\to$ $1-$Phenylethanol	$(2).$ $DiBAL-H$
$(C).$ Cyclohexanone $\to$ Cyclohexanol	$(3).$ $Zn(Hg) / \text{Conc. } HCl$
$(D).$ Phenyl benzoate $\to$ Benzaldehyde	$(4).$ $CH_3MgBr$

An organic compound $(A)$ with molecular formula $C_8H_8O$ forms an orange-red precipitate with $2,4-DNP$ reagent and gives a yellow precipitate on heating with iodine in the presence of sodium hydroxide. It neither reduces Tollens' or Fehlings' reagent,nor does it decolourise bromine water or Baeyer's reagent. On drastic oxidation with chromic acid,it gives a carboxylic acid $(B)$ having molecular formula $C_7H_6O_2$. Identify the compounds $(A)$ and $(B)$ and explain the reactions involved.

Compound $(A)$,$C_6H_{12}O_3$,when treated with $I_2$ in aqueous sodium hydroxide gives a yellow precipitate. When $(A)$ is treated with Tollens' reagent,no reaction occurs. When $(A)$ is hydrolysed and then treated with Tollens' reagent,a silver mirror is formed in the test tube. Compound $(A)$ will be

In the following reaction,
$CH_3-C \equiv CH$ $\xrightarrow[H_3O^+]{Hg^{2+}} X$ $\xrightarrow[PhCHO]{dil. NaOH} Y$
$X$ and $Y$,respectively,are

Which of the following is the correct order of reactivity of carbonyl compounds towards nucleophilic addition reactions?