Answer:
It will turn red
Explanation:
Bases will turn the litmus paper (impregnated with an acid-base indicator) blue.
Acids will turn turn the litmus paper (impregnated with an acid-base indicator) red.
Since the produced HCl is a strong acid, the litmus paper will turn red, when touching the HCl.
The red shows the presence of an acid, in this case HCl.
