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DemonstrationsChemical Reactions II › 5.2

Lecture Demonstrations

Chemical Reactions II: Oxidation/Reduction

5.2 Oxidation of Zinc by Hydrochloric Acid

Subjects: Oxidation/reduction, gas forming reaction, acid properties, net ionic equations, exothermic reactions.

Description: Observation of the oxidation of zinc metal by hydrochloric acid to form hydrogen gas and zinc chloride.


  • Mossy zinc (1 piece)
  • 1 M Hydrochloric acid, HCl‡
  • Petri dish
  • Tweezers
  • Flask (optional)
  • Balloons (optional)

‡HCl is located in the cabinet under the hood.

Procedure A:
Use the demo camera for displaying the reaction in ISB135.

  1. Add a small amount of HCl to the Petri dish or flask.
  2. Add a small piece of zinc metal to the HCl and observe the reaction. Hydrogen gas will be produced.

Optional: Put a balloon over the flask opening to collect the gas. Ignite the balloon.

Discussion: Zinc is oxidized by hydrochloric acid to form zinc chloride. In the process, hydrogen gas is produced. The reaction is given below.

Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)

Zn(s) + 2H+ → Zn2+(aq) + H2(g) (Net ionic equation)

Safety: HCl and zinc chloride are corrosive and can cause skin irritations or burns. Wear appropriate protective equipment, including gloves and safety glasses.

Disposal: Solutions of zinc chloride should be disposed in appropriate hazardous waste container.

References: For a more thorough description and variations see:

1. B.Z. Shakhashiri; Chemical Demonstrations: A Handbook for Teachers of Chemistry; Wisconsin; 1985; Volume 1; p. 25-26.

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