ZIMSEC O Level Combined Science Notes: Experiment: The corrosion of metals by acids
Aim: Investigating the corrosion of some metals by acids
Materials: 5 test tubes, dilute hydrochloric acid, granulated zinc, iron fillings/iron nail, copper foil, aluminium foil, magnesium ribbon, splint burner.
- Place a small piece of each of the above metals into each one of the test tubes
- Pour dilute hydrochloric acid into each test tube so that it just covers the metal
- Observe each of the mixture for a few minutes
- Place a thumb/cork over the mouth of one of the test tubs in which a gas is being produced in order to allow the gas to build up
- When you feel pressure over your thumb/ it looks like much pressure has build up remove the thumb and quickly insert a lighted splint into the mouth of the test tube.
Observations and results
|Metal||Rate of reaction||Level Corrosion|
|Magnesium||Rapid evolution of bubbles and vigorous reaction||Quickly disappears as it is corroded by the acid|
|Zinc||Fast evolution of bubbles/rapid reaction||Is quickly corroded|
|Aluminum||Slow evolution of bubbles||Is corroded by the acid|
|Iron||There is slow effervescence||The metal is eaten away and corroded|
|Copper||None apparent /No reaction||The metal is not corrected at all|
- Hydrogen gas is produced when the metals are corroded
- It burns with a pop sound when a lighted splint is inserted into test tube
- Copper does not react with the acid nor is it corroded
- Some metals are corroded by acid
- They react with hydrochloric acid to form a salt and hydrogen gas
- Copper does not react with dilute hydrochloric acid
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