A student is given a sample of a pure, white crystalline substance. Which of the following would be most useful in providing data to determine if the substance is an ionic compound? Examining the crystals of the substance under a microscope

A Determining the density of the substance

B Testing the electrical conductivity of the crystals

C Testing the electrical conductivity of an aqueous solution of the substance

Answer: Testing the electrical conductivity of an aqueous solution of the substance is the correct option.

Explanation:

An ionic substance is defined as the substance formed due to transfer of electrons (s) from one atom to another of the combining species.

For example, when a metal and a non-metal chemical combines then an electron will always be transferred from the metal to the non-metal.

Hence, a metal and non-metal always form an ionic bond.

It is known that water is a polar substance and polar or ionic substances readily dissolve in it.

So, when an ionic compound is dissolved in water then it will dissociate into ions. And, as electricity is the flow of ions or electrons hence, an aqueous solution of ionic substance is able to conduct electricity.

But an ionic compound in crystal form will not be able to conduct electricity because then ions are not present in free state.

Thus, we can conclude that testing the electrical conductivity of an aqueous solution of the substance, would be most useful in providing data to determine if the substance is an ionic compound.