Question

Which of the following is a good conductor of electricity?
A. Tap water
B. Distilled water
C. Sea water
D. Rain water

Answer 1

Hint: We know that the conductivity of water depends on the concentration of dissolved ions in solution. When salt is dissolved in water it dissociates into its components ions. This basically means that the salt molecule breaks up into two atoms with charge.

Complete step by step answer:
Salts dissociate into positive and negative ions in the solution, those ions can move around. Negative ions get attracted to the positive terminal, and give their electrons to the positive terminal. Positive ions get attracted to the negative terminal, and take electrons from the negative terminal. They become neutral in the process, and they generate a net electron flow. So sea water acts as a good conductor of electricity.
Water is a polar molecule. Sea water contains sodium cation and chlorine anion. The positive end attracts the negative chlorine ion and the negative end attracts the positive sodium ion. That’s enough to pull the salt molecule apart into free floating positive and negative ions. And that makes salt water conductive. It has mobile charges, and both positive and negative mobile charges. When you impose an electric field on salt water, by sticking electrodes into it, those ions move in the opposite direction in response to that field.
Therefore, the correct option is C.
Note:
It is known that, in sea water salt is present and salt is made up of \[{\rm{N}}{{\rm{a}}^ + }\] and \[{\rm{C}}{{\rm{l}}^ - }\]ions. When salt is mixed with water, aqua provides the dispersion media for the movement of ions and electrons, which is responsible for the conductance of electricity.