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)

NCERT Class 10th Science Chapter 1 Chemical Reactions and Equations

Answer 1

1)Na is oxidised and O2 is reduced
2)CuO is reduced and H2 is oxidised

Answer 2

1 na has gained o2 to form na20.. hence  na has been oxidised to na2o...therefore o2 has been reduced
2  cuo has lost  o2 to form cu.hence  cuo has been reduced to cu.h2 has gained o2 to form h20 ..hence h2 has been oxidised to h20