Question

The high boiling point of water is due to the presence of:
A. Dative bond
B. Covalent bond
C. Hydrogen bond
D. Vander Waals bond

Answer 1

Hint: The boiling point of a liquid is the temperature at which the vapor pressure of the liquid becomes equal to the atmospheric pressure of the liquid’s environment. At this temperature, liquid is converted into vapor. Moreover, hydrogen bonding is a special type of dipole-dipole attraction between the molecules.

Complete step by step answer:
The boiling point of the liquid depends upon the pressure of the surrounding. So, when the liquid is at high pressure, then it has a higher boiling point than the boiling point at normal atmospheric pressure. Furthermore, the boiling point of a substance is dependent on the pressure of its surrounding.
Now, the high boiling point of water is due to the presence of Hydrogen bond. Multiple hydrogen bonds occur simultaneously in water because of its bent shape and the presence of two hydrogen atoms.
Moreover, in the liquid state, the hydrogen bonds of water can break and reform, as the molecules flow from one place to another. The electrostatic attraction between the partial positive charge between the hydrogen atoms and the partial negative charge close to the oxygen atom allows the formation of a hydrogen bond.
The hydrogen bonding in water molecule is as shown:


Hence, option C is correct.

Note: Hydrogen bonding also occurs due to the unique physical properties, low surface tension, high vaporization energy and high specific heat. Another unique property of water caused by hydrogen bonds is the hydrophobic effect or exclusion of compounds containing carbon and hydrogen. Further, the hydrophobic effect is also important in the formation of cell membranes.