Question

Water is used as an insulator because:
A. It is a good conductor of heat
B. It is a bad conductor of heat
C. It is a good conductor of electricity
D. It is a bad conductor of electricity

Answer 1

Hint: Materials which conduct heat very well are known as good conductors and materials which do not conduct heat at all are called insulators. For the process of conduction to take place, electrons in a matter must be free to carry the heat or electricity forward. We will study the criteria for a substance to be an insulator and check how water is not following that criterion, as water is a well-known insulator.

Complete step by step answer:
Insulators are defined as the materials that keep energy such as electricity, heat, or cold from easily transferring through them. Thermal insulation is basically the reduction of heat transfer, that is, the transfer of thermal energy between objects at different temperatures, between the objects in thermal contact or in a range of radiative influence.
Conduction is a process of transfer of heat in which the thermal vibrations of the different particles of a medium is constantly transferred to the successive particle and thus the thermal energy is transferred from one side to the other Side. In the process of conduction, electrons play a very important role. For good conduction, electrons must be free.
In water, the electrons are engaged in chemical bonds and hence are not free to participate in the conduction. Materials which conduct heat very well are known as good conductors and materials which do not conduct heat well are known as bad conductors or insulators. Water thus is an insulator.
Hence, the correct option is B.

Note:
Conduction can be of various types, either thermal conduction or electricity conduction. Water is a bad conductor of heat but not a bad conductor of electricity, until or unless the water sample is of pure water. As the pure water does not contain any ions, it works as an electric insulator, while normal water works as a good conductor of electricity.