Ionic compounds show all of the following properties EXCEPT:

Explanation

The correct answer is Option C: All show polymorphism and isomerism.Ionic compounds typically do not exhibit isomerism because their structures are defined by the electrostatic attractions between ions, which do not allow for different spatial arrangements as seen in covalently bonded molecules. While some ionic compounds can show polymorphism, not all do, making this statement generally incorrect for all ionic compounds.Option A is incorrect because ionic compounds are usually solid at room temperature due to the strong forces holding the ions in a lattice structure. Option B is incorrect because ionic compounds conduct electricity when molten or dissolved in water, as the ions are free to move and carry charge. Option D is incorrect as ionic bonds are indeed non-directional, allowing ions to attract each other equally in all directions, forming rigid crystal lattices.