What did you see? (b) What might be the reason behind the change?

Question

Apparatus : Test tube, straw, lime water, etc. 

Procedure: Take freshly prepared lime water in a test tube. Blow air in it for some time through the straw and observe the lime water. Note the observation.

(a) What did you see?

(b) What might be the reason behind the change?

Answer 1

(a) When we blow air through the straw in freshly prepared lime water, it turns milky.

(b)

 

Freshly prepared lime water is obtained by dissolving lime (CaO) in water (H₂O).

When we blow air through the straw in lime water, carbon dioxide (CO₂) present in the air reacts with lime water to form white precipitate (insoluble substance) of Calcium Carbonate (CaCO₃) due to which lime water turns milky.