A-LevelChemistryIntroduction to organic chemistry9701/42 · Oct/Nov 2017 · Q810 Marks

Compound A can be produced from a plant hormone. [Figure 8.1: Structure of Compound A]

(a)(i)Compound A shows optical and geometrical isomerism. On the structure of A above, • draw a line through the bond(s) that give rise to geometrical isomerism, • circle all chiral carbon atoms.[2]
(a)(ii)Give the names of four functional groups present in A.[2]
(a)(iii)A molecule of A has 17 carbon atoms. State the number of carbon atoms that are sp, sp² and sp³ hybridised in A.[1]
(a)(iv)When A is reacted with an excess of hot, concentrated manganate(VII) ions, a mixture of three organic compounds is formed. A → X (C₁₀H₁₄O₇) and Y (C₃H₄O₃) and Z (C₄H₆O₃) Suggest the structures of Y and Z.[2]
(b)(i)Identify which spot corresponds to each compound. compound J CH₃COCO₂H K HO₂CCO₂H L CH₃CH₂COCH₂CH₃ spot[1]
(b)(ii)Explain your answers to (b)(i).[1]
(b)(iii)What is meant by the term R_f value?[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 (Oct/Nov 2017). The mark or mark type is shown in brackets.

[1] circle or asterisk on correct C atom only [1]
[1] lines through the two correct bonds only [1]
[2] ketone, (tertiary) alcohol, alkene, carboxylic acid two for each mark
[1] sp carbons = 0
[1] sp² carbons = 8
[1] sp³ carbons = 9
[2] (diagrams for Y and Z provided)
[1] J 2
[1] K 3
[1] L 1
[1] The more polar the compound and stronger attractive forces to the (polar) stationary phase ora: less polar compound and weaker attractive forces to the (polar) stationary phase
[1] R = retardation factor or retention factor or
[1] Rf=distance moved by compound from baseline over distance travelled by solvent front

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