Question

Identify the substances that are oxidised and the substances that are reduced in the following reactions.
(i) 4Na (s) + O₂ (g) → 2Na₂O (s)
(ii) CuO (s) + H₂ (g) → Cu (s) + H₂O (l)

Answer 1

(i) Sodium (Na) is oxidised as it gains oxygen and oxygen gets reduced.

(ii) Copper oxide (CuO) is reduced to copper (Cu) while hydrogen (H₂) gets oxidised to water (H₂O).