Answer: Option (a) is the correct answer.
Explanation:
Ionic salts are defined as the salts which tend to contain ionic bonds as there occurs transfer of electrons between its combining atoms.
So, when an ionic salt melts or it is dissolved in water then it will dissociate into its respective ions and as electricity is the flow of electrons or ions. Hence, this salt is then able to conduct electricity.
As covalent compounds are insoluble in water so, they do no dissociate into ions. Hence, they do not conduct electricity.
Similarly, metallic and network solids do not dissociate into ions either when melted or dissolved in water. Therefore, they also do not conduct electricity.
Thus, we can conclude that when a white crystalline salt conducts electricity when it is melted and when it dissolves in water then this bond is of ionic type.
