Which substance will give a positive iodoform test?

$CH_3CH=CHCHO$ $\xrightarrow[\text{Aldol condensation}]{OH^{-}}$ $\xrightarrow{\Delta} A$; Product $A$ is

What is formed when carbon monoxide reacts with $Cl_2$ in the presence of sunlight?

$HCHO$ was treated with a reagent $X$. The product formed upon hydrolysis in the presence of an acid gave $C_{2}H_{5}OH$. The reagent $X$ is

Give the reaction of $(a)$ acetaldehyde and $(b)$ acetone with $(i)$ $NaHSO_{3}$ and $(ii)$ $HCN$.

Assertion : $2, 2-$ Dimethylpropanal undergoes Cannizzaro reaction with conc. $NaOH$.
Reason : Cannizzaro reaction is a disproportionation reaction.