Question

Which of the following statements about the compound HCI is true?

Answer 1

Answer.
The answers is A; The physical and chemical properties of HCl are different from those of H2 and Cl2.

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

Answer 2

The answer should be a. The physical and chemical properties of HCl are different from those of H2 and Cl2. Although H2 and Cl2 can react to form HCl, they are different compounds so will have different properties both physical and chemical.