Question

Which statements about the conductivity of distilled water are correct?
(A) It possesses an almost non-conducting nature
(B) It is obtained by distillation of water several times
(C) It is contaminated with a little acid
(D) None of the above

Answer 1

Hint: The conductivity of fluids is due to the presence of electrical charges called ions, for example, $\text{ }N{{a}^{+}}\text{ }$ and$\text{ }C{{l}^{-}}\text{ }$. This is the reason why we always say that salt water is a good conductor of electricity, as it contains ions.

Complete step by step answer:
- Distilled water is purified water from which is free from all the impurities. Distilled water is obtained by evaporating the water, then the vapours are collected in a condenser. These vapours are of pure water and contain only the $\text{ }{{H}_{2}}O\text{ }$ molecules. With the help of distillation these water molecules can be collected in a flask and do not contain any other impurities. This is distilled water.
- Conductivity is a property of a solution. It is defined as the ability of electrolyte to conduct electricity .Conductivity of solution depends on the strength of electrolytes. The electrolyte which easily dissociates itself into the solution into its corresponding ions easily carries the electrical current through it.
- Thus, higher the number of ions in the solution, the better is the conductivity of the substance.
- Let’s understand this with the help of an activity:
- Let’s place a bulb and join the conducting end of the bulb with two wires.
- Let’s take R.O. purified water in a beaker and place the other ends of the two wires in this beaker. We observe that the bulb does not light.
- Let’s repeat the same experiment with salt water:
- Take out the wires from the RO purified water and clean its conducting ends with the help of sandpaper. Now place these wires inside the salt water. (Make sure the other ends are connected well with the bulb)
- We see the bulb glowing in the saltwater.
This happens because of the presence of $\text{ }N{{a}^{+}}\text{ }$ and $\text{ }C{{l}^{-}}\text{ }$ ions in saltwater, which help in the conduction of electricity.

Note: Note that an electrolyte can conduct electricity when it possesses free electrons or ions. These free electrons under the influence of potential difference move towards the positively charged electrode. The electrolyte in a solid-state or solid crystal state does not conduct electricity. They do not have free electrons. However, in solution electrolytes break down in their corresponding ions which can conduct electricity.