Chemistry · Oct / Nov 2017 · Paper 11 · Question 18

The formation of liquid water from hydrogen and oxygen may occur in three stages. 1 2H2(g) + O2(g) → 4H(g) + 2O(g) 2 4H(g) + 2O(g) → 2H2O(g) 3 2H2O(g) → 2H2O(l) Which stages are endothermic?

1. A1, 2 and 3
2. B1 only
3. C2 only
4. D3 only

As printed in the paper