Question

Look up and compare the normal boiling points and normal melting points of H2O and H2S. Based on these physical properties, which substance has stronger intermolecular forces? What kinds of intermolecular forces exist for each molecule?

Answer 1

Explanation:

Both melting and boiling point of water are much higher that that of H2S.

The MP and BP of water are 0°C and 100°C respectively whereas the MP and BP of H2S are -82°C and -60°C respectively.

Clearly, the intermolecular forces in H2O are much stronger than in H2S because, H2O has hydrogen bonding in it, which is both inter and intra. Whereas H2S has only weak van der waal force between their molecules. This is why boiling and melting points of H2O is more than that of H2S.

Hydrogen bonding is a particular type of dipole-dipole association which occurs between atoms of hydrogen bound to strongly electronegative atoms that are either fluorine, oxygen or nitrogen.

The hydrogen atom's partially positive side is drawn to the partially negative end of these atoms found in some other molecule. It is a strong binding mechanism between the molecules.