A pinch of NH4Cl is added to original solution. On adding excess of NH4OH to make the solution alkaline then add freshly prepared (NH4)2CO3 solution, a white precipitate is obtained.
Sr2+ + CO32- → SrCO3
White precipitate is soluble in acetic acid.
SrCO3 + 2CH3COOH → Sr(CH3COO)2 + H2O
Add (NH4)2SO4. Formation of white precipitate indicates the presence of Sr2+ ion.
Sr2+ + SO42– → SrSO4
You can also perform flame test. It gives crimson red colour to the flame.