Lewis structure of methanol: Primary Intermolecular forces: Hydrogen bonds. B.P: 78o C
Lewis structure of Ethane:It is non-polar and Hence only dispersion forces. B.P: -89 o C
1) The two liquids form an Non-Ideal solution. total volume is less than the individual liquids before mixing as the molecules attact each other. Examples are alcohol and water mixture. Hydrogen bonds are the forces.
2) Final temperature is higher because bonds are formed between the molecules A-B(Exothermic) and bonds break between A-A and B-B (both endothermic)
3) Reduction in volume clearely says that the two liquids participate in the reaction and new bond formation takes place between A-B which is Exothermic so the final temperatue is higher than the temperature before mixing.
4)If the final temperature is lower than the temperature before mixing, it implies that the heat is consumed for the bond breaking between the molecules.