Question

what is the answer of this question

Answer 1

NaCl(s) + conc. H2SO4 (l) –> NaHSO4 (s) + HCl(g)

The colour of blue litmus paper changes only in the presence of ions like hydrogen (H+) or hydronium (H3O+) ions. HCl can produce these ions only when in the form of aqueous solution. Hence dry HCl gas does not change the colour of dry litmus paper.Thus, wet blue litmus will turn into red