Question

Which of the next salts have better solubility in 1.0M NH3 than in distilled water? Na2CO3, KCl, AgBr, KNO3

Answer 1

The silver salt...........

Explanation:

The silver halides are as soluble as bricks in aqueous solution......i.e. we can represent the reaction by....

`Ag^(+) + Br^(-) rarr AgBr(s)darr`

Silver bromide precipitates from solution as a curdy, cream-coloured solid. We can increase the proportion of silver ion that remains in solution by adding aqueous ammonia, which participate in the following complexation equilibrium......

`AgBr(s) + 2NH_3(aq) rarr [Ag(NH_3)_2]^(+) + Br^-`

The equilibrium will move to the right hand side as ammonia is added.....These questions can be approached quantitatively given (i) `K_"sp"` for `AgBr`, and (ii) `K_f` for `[Ag(NH_3)_2]^+`.