(a) How is ethanoic acid obtained from ethanol? Write down the chemical equation of the reaction involved.

(b) How would you distinguish between ethanol and ethanoic acid by chemical test?
(c) Explain the formation of scum when hard water is treated with soap.

(a) When ethanol (ethyl alcohol) is heated in the presence of alkaline potassium permanganate solution or acidified potassium dichromate solution, it gets oxidised to ethanoic acid. This reaction is known as an oxidation reaction.
The chemical equation for the reaction is given below:
$CH_3CH_2OH + 2[O] \xrightarrow [or acidified K_2Cr_2O_7]{alkaline KMnO_4, Heat} CH_3COOH + H_2O$

(b) To differentiate between ethanoic acid and ethanol, chemically, carbon dioxide can be used:
Ethanoic acid releases carbon dioxide on reacting with sodium bicarbonate.
The chemical equation for the reaction is given below:
$CH_3COOH + NaHCO_3→CH_3COONa + CO_2 +H_2O$

On the other hand, ethanol does not give out a brisk effervescence (carbon dioxide) with sodium bicarbonate.

(c) Scum is formed when soap is used in hard water because a large amount of soap reacts with the magnesium and calcium ions of hard water producing an insoluble curdy precipitate that sticks to the clothes making them difficult to be cleaned.


Simply Easy Learning

Updated on: 13-Mar-2023


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