(a) What is the atomicity of sulphur?
(b) How do you bring the change of rhombic sulphur to monoclinic sulphur and vice versa?
(c) What is the action of conc. HNO₃ on sulphur?

(a) Atomicity of sulphur is 8. Its formula is S₈.(b) Rhombic sulphur, when heated to above 369K, changes to monoclinic sulphur. Monoclinic sulphur, on cooling to below 369 K reverts back to rhombic sulphur.
Rhombic sulphur Monoclinic sulphur(c) Conc. HNO₃ oxidises sulphur to sulphuric acid while the former is reduced to NO₂.
S(s) + 6HNO₃(aq) H₂SO₄(aq) + 6NO₂(g) + 2H₂O(l).