(i). A sample of MnSO₄.4H₂O is strongly heated in air. The residue is Mn₃O₄.

(ii). The residue is dissolved in 100 ml of 0.1N FeSO₄ containing dilute H₂SO₄.

(iii). The solution reacts completely with 50 ml of KMnO₄ solution.

(iv). 25 ml of the KMnO₄ solution used in step (iii) requires 30 ml of 0.1 N FeSO₄ solution for complete reaction.

Find the amount of MnSO₄.4H₂O present in the sample.

(a) 1 litre of a mixture of CO and CO₂ is taken. This mixture is passed through a tube containing red hot charcoal. The volume now becomes 1.6 litre. The volumes are measured under the same conditions. Find the composition of the mixture by volume.

(b) A compound contains 28 percent of nitrogen and 72 percent of metal by weight. 3 atoms of metal combine with 2 atoms of N. Find the atomic weight of metal.

Which of the following compounds are covalent?

The total number of electrons that take part in forming the bond in N₂ is