Answer.
The answers is A; The physical and chemical properties of HCl are different from those of H2 and Cl2.
Step-by-step explanation;
Hydrogen chloride is a gas, which is a molecule made up of a hydrogen and a chlorine atom bonded by a single bond.
The chemical and physical properties of HCl differs from those of hydrogen and chlorine. For example; they have different molecular weight; HCl is colorless, while chlorine is greenish yellow and hydrogen is colorless