In Cannizzaro reaction given below
2PhCHO $$\buildrel {\mathop {:OH}\limits^{\left( - \right)} } \over \longrightarrow $$ PhCH₂OH + $$PhC\mathop O\limits^{..} $$₂^(-)
the slowest step is :

Which of the following on heating with aqueous KOH, produces acetaldehyde ?

The two functional groups present in a typical carbohydrate are

Buna-$$N$$ synthetic rubber is a copolymer of :