Identify the substances oxidised and the substances reduced in the following reactions: (i) 4Na(s)+O_(2)(g)rarr2Na_(2)O(s) (ii) CuO(s)+H_(2)(g)rarrCu(s)++H_(2)O(l)

Identify the substances oxidised and the substances reduced in the fol

1.	Identify the substances oxidised and the substances reduced in the following reactions: (i) 4Na(s)+O_(2)(g)rarr2Na_(2)O(s) (ii) CuO(s)+H_(2)(g)rarrCu(s)++H_(2)O(l)
Answer» Solution :(i) In this reaction, sodium (Na) is changed into sodium oxide `(Na_(2)O)`. This is the addition of oxygen to sodium. Since addition of oxygen is CALLED oxidation, therefore, the substance sodium (Na) is oxidised. Oxygen `(O_(2))` is changed into `Na_(2)O`. Here, the addition of METAL to oxygen TAKES place. So, the substance reduced is oxygen. (ii) Here, COPPER oxide is reduced to copper metal whereas hydrogen is oxidised to water.