Objective
Prepare and test hydrogen on reaction of dilute acid with aluminum
Materials required:
- Aluminium foil
- Dilute HCL
- Test tube
- Dropper
- Test tube holder
Procedure:
- Take few small pieces of aluminum foil in a dry test tube
- Pour 10mL of dilute hydrochloric acid in the above test tube
- Wait for 10-15 minutes, till you observe small bubbles on aluminium foil
- Plug the mouth of test tube with thumb to stop liberated gas from leaking
- Take a burning match stick or burning candle near the mouth of the glass tube
Findings:
- On adding acid into a test tube containing aluminium foil, bubbles of some gas evolve.
- On bringing ignited candle near the mouth of the glass tube, the gas burns with “Pop” sound.
- When metals react with acids, they produce a salt as well as hydrogen gas. Think of MASH (Metal + Acid = Salt + Hydrogen).
Conclusions:
- Hydrogen gas is evolved in the reaction between aluminium and dilute hydrochloric acid.
Aluminum + Dilute Hydrochloric acid → Aluminum chloride + Hydrogen gas
- Hydrogen gas burns forming water, producing a sound, generally called pop sound.
Hydrogen gas + Oxygen gas (from air) → Water (pop sound)
Theory:
- Acids react with most metals and, when they do, a salt is produced. But unlike the reaction between acids and bases, we do not get water. Instead we get hydrogen gas.
- It doesn't matter which metal or which acid is used, if there is a reaction we always get hydrogen gas as well as the salt. However, how quickly the reaction goes depends on the metal used and how high up in the reactivity series it is.