Which of the following compounds is not ionic?Calcium oxidePotassium bromideHydrogen chlorideSodium chloride

Hydrogen chloride is not an ionic compound.

Here's why:

1. Ionic compounds are formed when a metal reacts with a non-metal. They involve the transfer of electrons from the metal atom to the non-metal atom.

2. Calcium oxide (CaO), potassium bromide (KBr), and sodium chloride (NaCl) are all ionic compounds. They are formed by the reaction of a metal (calcium, potassium, and sodium respectively) with a non-metal (oxygen, bromine, and chlorine respectively).

3. Hydrogen chloride (HCl), however, is not an ionic compound. Although it is formed by the reaction of a non-metal (hydrogen) with another non-metal (chlorine), it does not involve the transfer of electrons. Instead, the hydrogen and chlorine atoms share a pair of electrons, forming a covalent bond. Therefore, hydrogen chloride is a covalent compound, not an ionic one.