O-LevelChemistryOrganic Chemistry5070/21 · May/June 2020 · Q66 Marks
The structures of two carboxylic acids are shown. HO H-C-C-O-H H ethanoic acid HHHO H-C-C-C-C-O-H HHH carboxylic acid B
- (a)(i)An isomer of carboxylic acid B has the name methylpropanoic acid. What is the name of carboxylic acid B?[1]
- (a)(ii)What is the meaning of the term isomer?[1]
- (b)Vinegar contains ethanoic acid. Describe the formation of vinegar from ethanol.[2]
- (c)(i)Ethanoic acid reacts with calcium carbonate. Give the formula of the calcium salt formed in this reaction.[1]
- (c)(ii)Name the other two products formed in this reaction. ......................................................................... and .........................................................................[1]
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Mark scheme
Marking points from the official mark scheme (May/June 2020). The mark or mark type is shown in brackets.
- [1] butanoic (acid)
- [1] same molecular formula but different structures
- [2] aerial oxidation (of ethanol) / (ethanol) reacts with oxygen (1) in presence of bacteria (1)
- [1] Ca(CH3CO2)2 / Ca(CH3COO)2
- [1] water and carbon dioxide
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