Drawing and naming esters
3 marks · NormalEthanoic acid reacts with methanol when heated with a few drops of concentrated sulfuric acid.
State the name given to this type of reaction.
Draw the full structural formula of the ester formed in this reaction.
Explain briefly how the water molecule is formed during this reaction.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Esterification
(b) Structural formula showing methyl ethanoate: · must show COO linkage, CH3 group from acid, CH3 group from alcohol
(c) An H from the alcohol and an OH from the acid combine to form water (H2O).
Common mistakes: Naming reaction as condensation without esterification; Drawing incorrect structure (not methyl ethanoate); Describing removal of wrong atoms for water formation
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States that the reaction is esterification.
B2 (b) · 1 mark · Correct structural formula of methyl ethanoate (CH3COOCH3) with correct bonding.
B3 (c) · 1 mark · Correct explanation, e.g. H from alcohol and OH from acid form H2O.
Worked solution
(a) The reaction is called esterification. (1 mark)
(b) The full structural formula of the ester (methyl ethanoate) is:
or displayed as:
(1 mark)
(c) During this reaction, an H atom from the alcohol (methanol) and an OH group from the acid (ethanoic acid) combine to form water. (1 mark)