(b) What happens when carbon dioxide gas is passed through lime water
(i) for a short time?
(ii) for a considerable time?
Write equations of the reactions involved
Answers
Carbon dioxide reacts with limewater (a solution of calcium hydroxide, Ca(OH) 2), to form a white precipitate (appears milky) of calcium carbonate, CaCO 3. Adding more carbon dioxide results in the precipitate dissolving to form a colourless solution of calcium hydrogencarbonate..
Answer:
formation of water soluble calcium bicarbonate
When CO
2
is passed through lime water, it turns milky due to the formation of calcium carbonate which is sinsoluble in water.
limewater
Ca(OH)
2
+CO
2
⟶
milkiness
CaCO
3
+H
2
O
However, when excess of CO
2
is passed through this solution, the milkiness disappears. This is due to the formation of calcium bicarbonate which is colorless and soluble in water.
milkiness
CaCO
3
+H
2
O+
excess
CO
2
⟶
water soluble
Ca(HCO
3
)
2