Why is the boiling point of water high compared to hydrogen chloride?

Answer 1

Water and hydrogen chloride are both polar compounds (which is to say, the molecule has both positive and negative poles) but water is more polar than hydrogen chloride. Oxygen has a higher electronegativity than chlorine does, and consequently, there is a greater difference in electronegativity between oxygen and hydrogen than there is between chlorine and hydrogen. Consequently, there is a greater concentration of electrons at the oxygen atom than at the chlorine atom in these two molecules.

Polarity then leads to attraction between molecules (which align themselves so that negative poles can attract positive poles) and greater attraction between molecules will result in a higher boiling point.