Give two tests for hydrochloric acid.
Disclaimer: Any of the below mentioned four tests can be used to answer this question.
Tests for hydrochloric acid are as follows:
Litmus Paper test: It turns blue litmus red.
When a solution of lead nitrate is treated with hydrochloric acid, it gives a white precipitate of lead chloride.
Pb(NO3)2(aq) + 2HCl (aq) → PbCl2(s) + 2HNO3(aq)
White ppt.
Addition of silver nitrate solution causes formation of white precipitate of silver chloride with hydrogen chloride.
AgNO3(aq) + HCl(aq) → AgCl(s) + HNO3(aq)
White ppt.
Strong oxidising agents such as manganese dioxide, red lead, etc., liberate chlorine gas with concentrated hydrochloric acid. Chlorine is a greenish yellow gas with a pungent smell.
MnO2 + HCl → MnCl2 + H2O + Cl2↑