Water can dissolve more substances than any other liquid because ​

The correct answer is A. A water molecule is bent, and oxygen pulls the shared electrons towards itself, so the molecule has a permanent dipole with a partially negative oxygen end and partially positive hydrogen ends. This polarity lets water pull apart ionic lattices like NaCl and surround the ions (ion-dipole attraction). It also forms hydrogen bonds with polar molecules such as sugars and alcohols. That is the basis of the 'like dissolves like' rule, and it is why water is called the universal solvent, though that is a loose description since it cannot dissolve everything.

• B is wrong: water is a poor conductor of heat compared with metals, and heat conduction has nothing to do with solvency.
• C is wrong: high specific heat explains why water moderates coastal climate and body temperature. It does not explain dissolving power.
• D is wrong: water is an oxide of hydrogen, but that is only a chemical description. Hydrogen peroxide is also an oxide of hydrogen and is not a powerful universal solvent, so the description does not explain the property.

Concept: molecular polarity and intermolecular forces. For Mains, this links to water as a solvent in biological transport and to water chemistry in GS III and GS I.

Trap: candidates pick D because it is literally true, or C because they remember water's high specific heat. Ask what property actually causes dissolution.