Reaction of metals with oxygen
Metal reacts with oxygen to form metal oxides.
Metal + oxygen → metal oxide
Different metals react differently depending upon their reactivity
1. Sodium and potassium react with oxygen present in air instantly so these are always placed in kerosene oil.
4Na + O2 → 2Na2O
2. Magnesium, zinc, aluminium, lead like metals combine slowly with oxygen present in air. These metals forms layer of metal oxide on their surface which is hard and tough in nature. Due to this further reaction of these metals with oxygen is not possible. So these metals get protected by these metal oxide layer.
4Al + 3O2 → 2Al2O3
2Mg + O2 → 2MgO
3. Iron don’t react with oxygen even on heating but iron powder react fastly with oxygen on adding in fire.
4. Silver and gold don’t React with oxygen.