1) Methanol is known to be the simplest alcohol, and is used as an antifreeze agent, a solvent, a fuel and a denaturant for ethyl alcohol. It is also known as wood spirit, as it is obtained from the pyrolysis of food. Today it is prepared as: CO (g) + 2H2 (g) → CH3OH () Calculated, using the following data, what would be the enthalpy change for the reaction? (i) C(graphite) + 1/2 O2(g) → CO(g) DH = –110.5 kJ /mol (ii) C(graphite) + O2(g) → CO2(g) DH = –393.5 kJ /mol (iii) H2 (g) + 1/2 O2(g) → H2O(l) DH = –285.9 kJ /mol (iv) CH3OH () + 3/2 O2 (g) → CO2 (g) + 2H2O (l) DH = –726.6kJ /mol 2) Hydrogen sulfide or H2S gas results when bacteria like salmonella break down organic matter in the absence of oxygen. It has a foul odour of rotten eggs. It can also be formed as follows: S(s) + H2O (l) → H2S (g) +1/2 O2 (g) What would be the enthalpy for the reaction? (i) H2S (g) +3/2 O2 (g) → H2SO3 (l) DH = –357 kJ (ii) H2SO3 (l) → H2O (l) + SO2 (g) DH = 108.5 kJ (iii) S(s) + O2 (g) → SO2 (g) DH = –519.8kJ