If necessary, protect non-glass surfaces of an overhead projector with clear plastic. Dip one Q-tip into concentrated hydrochloric acid (HCl) and a second cotton swab into concentrated aqueous ammonia ...

5 min) Show the students that the HCl solution in the Erlenmeyer is colorless ... Indicators are flammable and slightly toxic if ingested. Hydrochloric acid is corrosive and sodium hydroxide is an ...