| Reactions of Lanthanum |
 Reactions with water |
| Lanthanum is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form lanthanum hydroxide
and hydrogen gas.
|
2La(s) + 6H2O(g) 2La(OH)3(aq) + 3H2(g) |
| Reactions with air |
| Lanthanum tarnishes slowly in air and burns readily to form lanthanum (III) oxide. |
| 4La(s) + 3O2(g)2La2O3(s) |
| Reactions with halogens |
| Lanthanum metal reacts with all the halogens to form lanthanum(III) halides. |
| 2La(s) + 3F2(g)2LaF(s) |
| 2La(s) + 3Cl2(g)2LaCl(s) |
| 2La(s) + 3Br2(g)2LaBr(s) |
| 2La(s) + 3I2(g)2LaI(s) |
| Reactions with acids |
| Lanthanum dissolves readily in dilute sulphuric acid to form solutions containing the aquated La(III) ion together with hydrogen gas.
|
| 2La(s) + 3H2SO4(aq)2La3+(aq) + 3SO42-(aq) + 3H2(g) |
La(s)