Why does dry HCl gas not change the colour of the dry litmus paper?

Q. Why does dry HCl gas not change the colour of the dry litmus paper?

1. No H₃O⁺ ions will be present, litmus changes colour only in the presence of H₃O+ ions
2. Blue litmus becomes dry in presence of dry HCl gas
3. HCl gas acts asa dehydrating agent
4. None of the options

Answer: No H₃O⁺ ions will be present, litmus changes colour only in the presence of H₃O+ ions