Question
Water is a liquid while hydrogen sulphide is a gas. Explain.
Solution
The intermolecular forces, namely hydrogen-bonding, in H2O are stronger than in H2S. This is because in H2O the bonds are more ionic and there is a larger partial positive charge on H and partial negative on O, so neighboring H2O molecules can bind to each other and cause a stronger network of bonded molecules, thus requiring more energy (higher temperature) to break these bonds and form a gas (where intermolecular forces no longer act).
