Question

A salt whose aqua solution gives no precipitate on addition of ammonium hydroxide to it but white precipitate on addition of sodium hydroxide to it

Answer 1

Explanation:

because the unknown salt will have sodium in it, so whn NaOH added to it common ion effect comes into effect and it shifts the reaction in backwards direction that is precipitation.

ASSUME given salt is CH3COONa

CH3COONa <=>CH3COO~ + Na+

NaOH ---> OH~ + Na+

in the above you can see the sodium ion concentration is increased i.e it disturbed the equilibrium,

so according to Le chateleirs principle the reaction shift in backwards direction.

HOPE THIS HELPS ;)