Question

Dry hydrogen chloride gas doesn't turn blue litmus to red where as aqeous hydrogen chloride acid does.why?

Answer 1

This is because dry HCl gas does not contain acidic properties.It is only acidic when it is aqueous (dissolved in water) without water no acid can turn litmus red.

Water facilitated the release and formation of hydronium ions (H30+) which alone HCl gas cannot make.

Hydronium ions are the reason for the acidic property of any substance.

Hope I helped.❤