Question

How can you use electrical conductivity to decide if a compound is ionic or covalent?

Answer 1

Ionic or covalent nature of a compound can be easily decided by its electrical conductivity. Here basic thing we need to keep in mind every time dealing with this type of question is that if a compound could not conduct electricity in liquid or solid state, it is showing that the compound is covalent . A controversial case exists in case of ionic compounds, that is, if a compound can conduct electricity whenever in molten state or dissolved in solution , it will be an ionic compound. Next factor related to this kind of question analysis is that ionic bonds will be between a metal and non-metal whereas covalent bond is between two non – metals.

Complete answer:
First of all we should know that compounds which are conducting electricity are strongly held together by the electrostatic force of attraction.
In this case, there will be positively charged and negatively charged molecules which are cation and anion respectively. But the main fact that exists here is that these compounds actually do not conduct electricity in their solid state which means the compound will be covalent in nature.
Therefore, the chance of conducting electricity will be followed only if the compound is dissolved in water which results in dissociation of ions by breaking the covalent bond that existed before. The dissociation will result in conduction of electricity.
Different case to mention here is that a compound can also conduct electricity without the presence of water , when cations and anions begin to flow as a result of high temperature resulting in transformation of the compound to become liquid . Compounds which do not dissociate into ions also do not conduct electricity . These can be proved by constructing a simple circuit setup having a light bulb as indicator to test conductivity of compounds which is aqueous in nature. The test compound included in the setup will complete the circuit and will turn on the bulb if it is able to conduct electric current. If it conducts it will be an ionic compound, if it does not conduct then it will be a covalent compound.

Note: To deal with this type of question , we have to know the nature of conductivity in liquids as well as in solids. Next thing we have to keep in short is about experiment setup to test conductivity which is an easy way to find the conductivity in solid and liquid state. We can easily determine the bonding in a compound as every compound which is formed between metal and non-metal is ionic in nature. One of the examples is sodium chloride having metal as sodium and non-metal as chlorine. And when they are formed between nonmetal atoms , it will be covalent in nature. One example is the nitrogen diatom where the nitrogen is a non-metal.