A4 The structure of malic acid is shown. [Figure 8.1: Structural formula of malic acid, H-OOC-CH(OH)-CH₂-COOH]

1. (a)Malic acid is a carboxylic acid because it contains a –COOH group. Malic acid also contains an -OH group. Name the homologous series of compounds which contain the -OH group.[1]
2. (b)A diester of malic acid has the formula shown. H7C3OOC-CH(OH)-CH2-COOC3H7 What reagent and conditions are needed to make this diester from malic acid? reagent conditions[2]
3. (c)When heated, malic acid forms fumaric acid. HOOC-CH(OH)-CH2-COOH → HOOC-CH=CH–COOH + H2O malic acid fumaric acid How can aqueous malic acid and aqueous fumaric acid be distinguished when aqueous bromine is added to a sample of each?[2]
4. (d)(i)The structure of compound A is shown. [Figure 9.1: Structural formula of compound A, HOOC-CH=CH-OH, showing two carbons with a double bond between them, one carbon bonded to -COOH and H, the other carbon bonded to -OH and H.] Compound A can undergo two types of polymerisation. Name these two types of polymerisation. 1. 2.[2]
5. (d)(ii)For one of these types of polymerisation, draw a section of the polymer to show two repeat units.[2]

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