Element A burns in nitrogen to give an ionic compound B. Compound B reacts with water to give C and D. A solution of C becomes 'milky' on bubbling carbon dioxide. Identify A, B, C and D.

Arrange the following sulphates of Alkaline earth metals in order of decreasing thermal stability : BeSO₄, MgSO₄, CaSO₄, SrSO₄

Explain the difference in the nature of bonding in LiF and LiI.

Complete and balance the following reactions:
Ca₅(PO₄)₃F + H₂SO₄ + H₂O $$\buildrel {Heat} \over \longrightarrow $$ ........ + 5CaSO₄.2H₂O + ........