Question

Give an example of activity to show that metals burn in air to form base.

Answer 1

Clean a magnesium ribbon about $\text{2 cm}$ long by rubbing it with sandpaper. Hold it with a pair of tongs. Burn it using a spirit lamp or burner and collect the ash so formed in a watch-glass. Burn the magnesium ribbon keeping it as far as possible from your eyes. When magnesium ($Mg$) ribbon is burnt in oxygen($O_2$), it gets converted to magnesium oxide ($MgO$). To collect this rust of magnesium oxide and dissolve it in a little amount of water. If we shake this mixture and test it with litmus paper then we observe that red litmus turns blue. This is because when we dissolve magnesium oxide ($MgO$) in water($H_{2}O$) it forms magnesium hydroxide($Mg(OH{)}_2$). Magnesium hydroxide is basic in nature.

So we can conclude that when metal burns in the air they form a base.