Key Stage 3
Meaning
An acid is a chemical dissolved in water that has a pH less than 7.
About Acids
- Acids can be an Irritant, Harmful or Corrosive and should be handled with care.
- When an acid is dissolved in solution the Hydrogen atoms in the molecule become free to move around and these are what make it an acid.
- Acids can be concentrated or dilute.
- Acids can be weak or strong which depends on the type of acid and the concentration.
- Acids turn Litmus paper red.
- Acids turn Universal Indicator pink, red, orange or yellow depending on the strength of the acid.
Some common Acids you should know:
- Hydrochloric Acid - Found in the stomach.
- Citric Acid - Found in Citrus fruits.
- Ethanoic Acid - The common name for vinegar.
- Sulphuric Acid - Found in Electrical Cells.
Examples
 |
 |
 |
| Car batteries contain Sulphuric Acid at around pH 0. | Citrus fruits have Citric Acid in them at around pH 2. | Vinegar is made of Ethanoic Acid at around pH 2.5. |
 |
 |
 |
| Fizzy drinks contain Carbonic Acid at around pH 3. | Coffee is slightly acidic at pH 5. | Milk has a small amount of Lactic Acid giving it pH 6.5. |