Question

Look at the figure and answer the following questions.

(a) What change would you observe in the calcium hydroxide solution taken in tube B ?
(b) Write the reaction involved in test tubes A and B respectively.
(c ) If ethanol is given instead of ethanoic acid, would you expect same change ?
(d) How can a solution of lime water be prepared in the laboratory ?

Answer 1

(a) It would become milky.
(b) In test tube A, ethanoic acid reacts with sodium carbonate to form sodium ethanoate along with carbon dioxide. The gas is evolved accompanied by brisk effervescence.
`underset((A))(CH_(3)COOH)+Na_(2)CO_(3)toCH_(3)COONa+CO_(2)+H_(2)O`
In test tube B, calcium hydroxide reacts with carbon dioxide to form calcium carbonate which is milky in colour.
`Ca(OH)_(2)+CO_(2)tounderset(("milky"))(CaCO_(3))+H_(2)O`
(c) No, it would be different. No chemical reaction is possible between ethanol and sodium carbonate.
(d) Lime water is prepared by keepinig suspension of calcium hydroxide overnight in a beaker. the solution is decanted and is transferred to another beaker. if contains traces of calcium hydroxide and is called lime water.