Splitting of signals in $NMR$ spectroscopy is caused by

What is formed when benzaldehyde reacts with chlorine in the absence of a catalyst?

Which of the following does $NOT$ give a yellow precipitate when reacted with a $(NaOH + I_{2})$ mixture?

Compound $A$ $(C_3H_6O)$ undergoes the following reactions to form $B$ and $C$. Identify $A, B$ and $C$.

Identify the final product in the following reaction sequence: $R-CHO$ $\xrightarrow{HS-(CH_2)_3-SH}$ $\xrightarrow{n-BuLi}$ $\xrightarrow{D_2O}$ $\xrightarrow{HgCl_2/CdCO_3, H_2O} \text{Product}$

The product which is not expected to be formed in the following reaction is:
$C_6H_5CHO + CH_3CH_2CHO \xrightarrow{OH^-(aq.), \Delta} \text{Product}$