The reaction between calcium and oxygen
| Calcium | + | Oxygen | → | Calcium oxide |
| 2Ca | + | O2 | → | 2CaO |
Calcium burns with an intense orange flame. The calcium oxide produced is also known as quicklime or burnt lime and is used in many industrial processes. Calcium oxide is soluble in water where it produces calcium hydroxide which has a pH of approximately 13 (a very strong alkali).
