Question

Pure water is a _________ conductor of electricity.

Answer 1

Hint: Conduction of electricity requires mobile carriers of charge. Water in its pure form cannot be ionised into its constituents charged species.

Step-by-Step Solution:
Let us first try and understand what a good conductor of electricity really possesses which differentiates it from other substances which are not-so-good conductors of electricity.
Electricity is the phenomenon of flow of current through a body or medium. Current is the flow of charges across a potential difference. Charges are nothing but species that either lack electrons or have an excess of it. The former is referred to as a positive charge whereas the latter is called a negative charge. In actuality there is nothing called as a positive charge, because the only entity that is shareable between atoms are electrons and they have a negative charge. So, less electrons than normal, is conventionally called positive charge.
The wires that we use in our homes are good conductors of electricity because the materials used to build them have free electrons which behave as the charge carriers. The solution of sodium chloride in water is a good conductor of electricity because of the ions that act as the charge carriers. The ions are entities that derive themselves from neutral elements either by gaining or donating electrons. This completely depends on their individual tendencies.
As it happens to be, pure water does not have species that will carry the charge and move freely in the solution. The water molecules can only dissociate into protons and hydroxide ions when an electrolyte is present or there are other impurities which ionise the water molecules.

Therefore, the above answer is: Pure water is a bad conductor of electricity.

Note: It should be noted that there are many other polar liquids other than water that are bad conductors of electricity because they are unable to ionise themselves. These liquids are therefore very good solvents in which various reactions can be carried out without the molecules of liquid reacting themselves.