The major product of the following reaction is :

In order to oxidise a mixture of one mole of each of FeC₂O₄, Fe₂(C₂O₄)₃, FeSO₄ and Fe₂(SO₄)₃ in acidic medium, the number of moles of KMnO₄ required is :

The size of the iso-electronic species Cl^–,  Ar and Ca²⁺ is affected by :

If solublity product of Zr₃(PO₄)₄ is denoted by K_sp and its molar solubility is denoted by S, then which of the following relation between S and K_sp is correct ?