The reaction between sodium and oxygen
| Sodium | + | Oygen | → | Sodium oxide |
| 4Na | + | O2 | → | 2Na2O |
Sodium burns with a bright yellowy orange flame. Once burnt, the sodium oxide left is a white colour. Sodium oxide is soluble in water and forms sodium hydroxide with a pH of between 13 and 14 (a very strong alkali).
