Question

An element X when heated is oxygen, above 300 ${}^{\circ }C$ burns with a pale blue flame to give a colourless gas Y and traces of gas Z. Identify X, Y and Z.

Answer 1

X is S (sulphur)

Y is $S{O}_2$

Z is $S{O}_3$

S + O₂ → SO₂

_{2 SO2 + O2 → 2 SO3}