Question

Is there any other gas than $ C{O_2} $ that turns limewater milky?

Answer 1

Hint: A dilute aqueous solution of calcium hydroxide is known as lime water. At normal temperature, calcium hydroxide ( $ Ca{(OH)_2} $ ) is only slightly soluble in water. Calcium hydroxide can be prepared by mixing calcium hydroxide with water and eliminating any undissolved solutes.

Complete Step By Step Answer:
To detect the presence of $ C{O_2} $ , lime water is commonly used. Carbon dioxide combines with lime water to generate calcium carbonate, an insoluble milky substance.
 $ C{O_2} + Ca{(OH)_2} \to CaC{O_3} + {H_2}O $
Sulphur dioxide reacts with lime water ( $ Ca{(OH)_2} $ ) and forms calcium sulphite as a product.
 $ S{O_2} + Ca{(OH)_2} \to CaS{O_3} + {H_2}O $
The colour of calcium sulfite is milky white.
Due to the production of calcium hydrogen sulphite, the milkiness vanishes. Calcium hydrogen sulphide is water soluble.
 $ CaS{O_3} + S{O_2} + {H_2}O \to Ca{(HS{O_3})_2} $
Hence, $ S{O_2} $ (Sulphur dioxide) turns lime water milky due to the formation of calcium sulfite ( $ CaS{O_3} $ ).
Additional Information: Slaked lime ( $ Ca{(OH)_2} $ ) is calcium hydroxide ( $ Ca{(OH)_2} $ ).
The reaction of water with calcium oxide produces calcium hydroxide.
 $ CaO + {H_2}O \to Ca{\left( {OH} \right)_2} $
When calcium oxide is combined with water, a small amount of calcium oxide dissolves, resulting in limewater.
We can detect carbon dioxide and sulphur dioxide using lime water.
Carbon dioxide has no odour; however, sulphur dioxide has a strong odour.
Sulphur dioxide changes the colour of potassium dichromate paper to green, whereas carbon dioxide has no effect on the colour of potassium dichromate paper.

Note:
Lime water is known to turn into milk when exposed to carbon dioxide. This occurs as a result of the formation of insoluble calcium carbonate. Calcium sulphide is formed when sulphur dioxide reacts with calcium hydroxide to form a milky precipitate, but it takes longer to form than calcium carbonate.