Acetaldehyde cannot give:

$C_6H_5CHO + HCN \to C_6H_5-CH(OH)-CN$. The product would be

For the reaction,the product expected is:

$CH_3CHO + NH_2OH \to CH_3-CH=N-OH$
Under which condition does the above reaction occur?

The major aromatic product $C$ in the following reaction sequence will be :

Given the reactions:
$CaOCl_2 + H_2O \longrightarrow Ca(OH)_2 + X$
$X + CH_3CHO \longrightarrow Y$
$Y + Ca(OH)_2 \longrightarrow CHCl_3$
What is '$Y$'?