Question

(a) How are carboxylic acids different from mineral acids from ionisation point of view?
(b) Describe an activity to show how ethanoic acid reacts with sodium carbonate. Name the gas evolved. How can it be tested?
(c) State the principle on which the cleasing action of soap is based.

Answer 1

(a) Carboxylic acids (organic acids) are less ionised in solution as compared to mineral acids `(Na_(2)CO_(3))` solution `H_(2)SO_(4)etc.)` due to this reason, these are weaker acids than the mineral acids.
(b) Take a small volume of ethanoic acid in a tube. add a few drops of sodium carbonate `(Na_(2)CO_(3))` solution prepared in water to the tube. A clourless gas with brisk effervescence will evolve. when the gas is passed through lime water, it will become millky.
`Na_(2)CO_(3)(aq)+2CH_(3)COOH(aq)to2CH_(3)COONa(aq)+H_(2)O(l)+CO_(2)(g)`
`underset("Lime water")(Ca(OH)_(2)(aq))+CO_(2)(g)tounderset(("Milky"))(CaCO_(3)(s))+H_(2)O(l)`
(c) The cleansing action of soap is based on its tendency to act as a bridge between water ad oil drops containing dirt particles. As a result, oil and water get mixed. they form a stable emulsion also called micelle. This helps in removing oil drops containing dirt particles from clothes. the clothes become clean.