A metal oxide is reduced by heating it in a stream of hydrogen. After complete reduction, it is found that 3.15 gm of the oxide has yielded 1.05 gm of the metal. It may be inferred that the
7. The heats of vaporisation of CS2, C2H5OH &H2O are 26.8, 38.6 & 40.6 KJ/kg mole respectively. The order of decreasing inter-molecular forces in these liquids is