Question

when the gas formed on heating limestone is passed through freshly prepared lime water , the lime water turn milky.

Answer 1

On heating of lime stone ( Calcium Carbonate ) carbon dioxide gas is liberated. If carbon dioxide gas passed through the lime water it turns milky white due to precipitation of Calcium Carbonate (insoluble in water ), and if passing of carbon dioxide gas is continue, the milky white lime solution get again clear due to conversion of Calcium Carbonate into Calcium bi Carbonate which is soluble in water.

Hope it helps!

Answer 2

Answer:

Explanation:

(i) On heating, limestone undergoes thermal

decomposition to form calcium oxide (quick

lime) and carbon dioxide.

CaCO3(s) ∆ CaO(s) + CO2

↑

quick lime

(ii) Calcium oxide when dissolved in water forms

Calcium hydroxide (lime water).

CaO(s) + H2

O(l) → Ca(OH)2(aq)

Calcium

hydroxide

(iii) When carbon dioxide is passed through lime

water it turns milky due to formation of white

precipitate of Calcium carbonate.

Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2

O(l)

Calcium

carbonate