Which of the following does not form a stable hydrate on addition of $H_2O$?

In the presence of a dilute base,$C_6H_5CHO$ and $CH_3CHO$ react together to give a product. The product is

The reaction of $A$ to give $B$ and $C$ as shown in the reaction scheme is an example of:
$CH_2=CH_2$ $\xrightarrow[2. Zn/H_2O]{1. O_3} A$ $\xrightarrow{Conc. NaOH} B + C$
(Where $B$ is an alcohol and $C$ is a sodium salt of a carboxylic acid)

Chlorine reacts with ethanol to give

Reduction of aldehydes and ketones to hydrocarbons takes place in the presence of:

Benzaldehyde can be converted to benzyl alcohol in concentrated aqueous $NaOH$ solution using