Hydrogen chloride gas can be prepared by the following reaction.

Hydrogen chloride may be formed by the direct combination of chlorine (Cl 2) gas and hydrogen (H 2) gas; the reaction is rapid at temperatures above 250 °C (482 °F). The reaction, represented by the equation H 2 + Cl 2 → 2HCl, is accompanied by evolution of heat and appears to be accelerated by moisture.

Explanation:

answer; (d) all matter is composed of small particles, which combine to make larger objects;