Explain why aldoses react with bendict's solution and `PhNHNH_(2)`, but not with `NaHSO_(3)`.

Explanation

Reaction of Benedict's solution and `PhNHNH_(2)` is the reaction of `CHO` group, in which the open-chain aldehyde form is in equilibrium with the cyclic hemiacetal form.
Fehling's, Benedict's, and osazone reactions are irrevesible. The equilibrium shifts to the open-chain aldehyde structure and they react.

With `NaHSO_(3)`, addition reaction is reversible and enough aldehyde remains in equibrium with the bisulphite adduct to satisfy the equilibrium towards the hemiacetal form hence no reacton takes place.