Which ion will most likely form a precipitate when reacted with so42 ?
сі-
k+
na+
ba2+

Explanation:

option A:

is an anion and is also an anion.So,there is no reaction.

option B:

reacts with to form .

Since is a first group element,all its salts are soluble in water.

Hence no precipitate is formed.

option C:

reacts with to form .

Since is a first group element,all its salts are soluble in water.

Hence no precipitate is formed.

option D:

reacts with to form .

Solubility of sulphates of second group elements decrease down the group.

So, is a precipitate.