which ion is present when you add copper(2) sulphate solution followed by sodium thiosulphate solution?

Question

on doing this test it was observed that a blue green precipitate was formed. how correct is this and if not what would be the correct observation?

Answer 1

Which question do you want answered anyway?
It seems to be that the sodium thiosulfate would be basic, in which a copper(II) complex such as [Cu(OH)4]-2 could form.