Question

Give reason:
1. Dry hydrogen chloride gas does not turn blue litmus to red, whereas dilute hydrochloric acid does.

Answer 1

Dear student. The dry hydrogen chloride does not turn blue litmus red whereas the dilute hydrochloric acid does. This is because hydrochloric acid in dilute or aqueous solution dissociates into H+ and Cl- ions and thus due to the H+ ions it changes the colour of the litmus whereas in the dry state the dissociation of hydrochloric acid is not possible so no H+ions would be released and no change in litmus would be observed. Regards