Benzaldehyde and acetaldehyde can be differentiated by

An organic compound $A$ reacts with methyl magnesium iodide to form an addition product,which on hydrolysis gives compound $B$. Compound $B$ gives a blue color in the Victor Meyer test. What are compounds $A$ and $B$ respectively?

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

Column-$I$ (Reactions)	Column-$II$ (Reagents)
$(i)$. Benzophenone $\rightarrow$ Diphenylmethane	$(a)$. $LiAlH_4$
$(ii)$. Benzaldehyde $\rightarrow$ $1-$Phenylethanol	$(b)$. $DIBAL-H$
$(iii)$. Cyclohexanone $\rightarrow$ Cyclohexanol	$(c)$. $Zn(Hg) / \text{Conc. } HCl$
$(iv)$. Phenyl benzoate $\rightarrow$ Benzaldehyde	$(d)$. $CH_3MgBr, H_2O$

Which one of the following compounds will be most readily dehydrated?

Which of the following,on reaction with $50\%\,KOH$,gives the corresponding alcohol and acid salt?

The treatment of $Ph_2C(OH)CH_2NH_2$ with $NaNO_2 - HCl$ gives a product $(P)$ which on oxidation gives benzoic acid only. Identify the product $(P)$.