The correct options are
A Ba2+ and Ca2+ ions can be separated by adding SO2−4 ion in acetic acid medium
B Golden yellow PbI2 dissolves in hot water to give a colorless solution
D The sulphide ion gives with alkaline sodium nitroprusside, a violet color
Option (A),(B),(D) are correct.
Salts of cobalt gives a blue flame color, salts of copper gives a green flame color, and nickel gives a brown flame color.