Assertion - HCl gas does not change the colour of dry blue litmus paper.
Reason - HCl gas dissolves in the water present in wet litmus paper to form H+ ions.
Answers
Answer:
(A) Assertion And Reason Both Are Correct And Reason Is
The Correct Explanation Of Assertion
Assertion : HCl gas doesn't change the colour of dry blue litmus paper.
Reason : HCl gas dissolves in the water present in wet litmus paper to form H⁺ ions.
answer : assertion and reason both are correct and the reason is perfect explanation of assertion.
explanation : HCl gas doesn't show its acidic character without dissolving in water. because water dissociates it into H⁺ and Cl⁻ ions. here H⁺ shows acidic character. an acid is the proton (H⁺) donor. and the solution of HCl has protons to donate them to others. so to show acidic character of HCl gas, it needs to dissolve in water.
therefore assertion is correct. i.e., HCl gas does not change the colour of dry blue litmus paper. because dry litmus doesn't have water molecules to dissociates the HCl into ions.
reason is also correct and the correct explanation of assertion : wet litmus paper have water molecules in which HCl gas dissolves to form H⁺ ions. and H⁺ ions change the colour of blue litmus paper into red.