Question

will blue litmus paper change to red when brought in contact with dry hcl gas if no explain why

Answer 1

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The colour of litmus paper changes only in the presence of ions like hydrogen (H+) or hydronium (H3O+) ions. HCl can produce these ions only in the form of aqueous solution.

Hence dry HCl gas does not change the colour of dry litmus paper. ... Litmus is turned turned red by arhenius acids because of their H+ ions .

Answer 2

because of absence of water