Explain the action of the following reagents on acetophenone:

Conc.${\mathrm{HNO}}_3$ in the presence of Conc.${\mathrm{H}}_2{\mathrm{SO}}_4$.

How can you bring out the following conversions?

Methanal to ethanal

How can you bring out the following conversions?

Ethanal to 2-hydroxy butanoic acid

How can you bring out the following conversions?

Acetylene to acetone.

What happens when

Formaldehyde is treated with ${\mathrm{NH}}_3$ ?

What happens when acetylene is passed through dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$ in presence of ${\mathrm{HgSO}}_4$.