Dip the piece of the pH paper into the test solution of the and quickly remove it. Check the color of the pH paper and compare it to the color pH scale enclosed with the paper pack to assign pH of the acid solution. The paper's red color that corresponds to pH of 2 or below is indicative for hydrochloric acid.
Test for Hydrochloric acid can be done by the litmus paper.
When we dip a blue litmus paper into the Hydrochloric acid ,it turns into into red.
When we drop few zinc granules into the the Hydrochloric acid , it releases Hydrogen gas.