I know that HCl is a compound whose 1 molecule is composed of 1 hydrogen and 1 chlorine atom bonded co-valently to each other, the bond being polar co-valent. It exists in gaseous state at room temperature. When HCl gas is dissolved in water, it dissociates to furnish H+ ions and thus HCl qualifies the definition of an acid. My question is:When is HCl known as an acid? When it is in the gaseous state or when it is dissolved in water to give an aqueous solution? Also what is the difference between an aqueous solution of HCl gas and liquid HCl?Is liquid HCl also an acid?