Question

(a) What happens when ethanol reacts with ethanoic acid in the presence of a little concentrated sulphuric acid? Write the equation of the reaction involved.
(b) What happens when ethanol is heated with concentrated sulphuric acid at \[{170^0}C\]? Write the equation of the reaction which takes place.

Answer 1

Hint: We have to know that the ethanol is also known as ethyl alcohol which is a chemical compound having the formula \[C{H_3} - C{H_2} - OH\] or \[{C_2}{H_5}OH\]. This is a volatile liquid and does not have any color. Ethanoic acid is also known as acetic acid. And this chemical compound has the molecular formula, \[C{H_3}COOH\]. And the sulphuric acid is a concentrated acid with formula, \[{H_2}S{O_4}\]. When ethanol reacts with ethanoic acid in the presence of concentrated acid, there is a formation of an ester.

Complete answer:
(a) When ethanol is reacted with ethanoic acid in the presence of concentrated sulphuric acid, there is a formation of sweet smelling ester which is known as ethyl ethanoate with the elimination of water. The reaction can be written as,
\[C{H_3}COOH + {C_2}{H_5}OH\xrightarrow{{conc.{H_2}S{O_4}}}C{H_3}COO{C_2}{H_5} + {H_2}O\]
     Ethyl ethanoate
There is a chance of a reverse reaction by the reduction process. And here the sulphuric acid acts as a catalyst and a dehydrating agent which helps for the removal of water molecules from the ethanol as well as the carboxylic acid.
(b) When ethanol is heated with concentrated sulphuric acid at \[170^\circ C\], there is a formation of ethene by the dehydration of ethanol. Let’s see the reaction;
\[C{H_3} - C{H_2}OH\xrightarrow[{Dehydration}]{{conc.{H_2}S{O_4},{{70}^o}C}}C{H_2} = C{H_2} + {H_2}O\]

Note:
By the reaction of ethanol with acetic acid in the presence of sulphuric acid, form an ester which is known as ethyl acetate. The sulphuric acid will help with the elimination of water. And when ethanol is heated with concentrated sulphuric acid, the ethanol gets dehydrated and forms an unsaturated hydrocarbon. Hence, this reaction is known as dehydration reaction by the removal of water molecules from ethanol.