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

Mounica observed that the dry HCl gas was not turned the dry blue litmus paper into red colour. Jahnavi explained the reason to Mounica by asking her some questions. What would be those questions ?

Which of the following can NOT change the colour of litmus paper

___gas changes the colour of lime water into milky white.

Sunitha dipped a litmus paper in a solution of pH 14. The litmus paper did not change its colour. The type of litmus she used is

What is the change you observe in litmus paper with acid ?

Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below. (a) What will be the action of gas on (i) dry litmus paper? (ii) moist litmus paper? (b) Write a balanced chemical equation for the reaction taking place.

Assertion (A) : Dry HCl gas is acid. Reason(R) : Acids turn blue litmus paper into red.

Which substance does not show any colour with litmus ?