Question

Magnesium ribbon is burnt and the ash formed is mixed with water. Now answer the following:

(a) Write equation for the burning of magnesium.

(b) What will happen when the mixture of ash and water is added to

(a) blue litmus solution and

(b) red litmus solution.

(c) Name the substances formed by mixing ash and water. Is acidic or basic ?

Answer 1

(a) 2Mg + O₂ > 2MgO (Magnesium oxide)

(b) When blue litmus is added to a solution of magnesium ash and water it does not change in colour. But on adding red litmus, the colour of litmus turns blue. This is because the solution of magnesium oxide is alkaline therefore, turns red litmus to blue.

(c) When Magnesium oxide ash is mixed with water it forms Mg (OH)₂ which is alkaline.