Classify whether HCl is a strong or weak acid, or a strong or weak base, or salt.

HCl is hydrochloric acid.  It is a strong acid.  All of the mineral acids like HBr, HI, H2SO4, and HNO3 are strong acids.  The pH of most any strength of an HCl solution is 1 since HCl completely dissociates into H+ and Cl-.  Since it completely ionizes in water, it is not a weak acid but a strong acid.  It is not a base at all, weak or strong.  It is also not a salt.  Even though it is composed of two ions, HCl is not considered a salt because the term salt is usually used to describe a compound made of ions that forms a solid in the absence of solvent.  In the absence of any water, hydrogen chloride (HCl) is actually a gas.