The average molar mass of chlorine is 35.5 g mol^–1. The ratio of ³⁵Cl to ³⁷Cl in naturally occuring chlorine is close to :

A crystal is made up of metal ions 'M₁' and 'M₂' and oxide ions. Oxide ions form a ccp lattice structure. The cation 'M₁' occupies 50% of octahedral voids and the cation 'M₂' occupies 12.5% of tetrahedral voids of oxide lattice. The oxidation numbers of 'M₁' and 'M₂' are, respectively :

The correct match between Item-I (starting material) and Item-II (reagent) for the preparation of benzaldehyde is :

Item-I	Item-II
(I) Benzene	(P) HCl and SnCl2, H3O+
(II) Benzonitrile	(Q) H2, Pd-BaSO4, S and quinoline
(III) Benzoyl Chloride	(R) CO, HCl and AlCl3

For a reaction,
4M(s) + nO₂(g) $$ \to $$ 2M₂O_n(s)
the free energy change is plotted as a function of temperature. The temperature below which the oxide is stable could be inferred from the plot as the point at which :