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Date November 2011 Marks available 2 Reference code 11N.2.hl.TZ0.9
Level HL Paper 2 Time zone TZ0
Command term State Question number 9 Adapted from N/A

Question

Consider the following reactions.

N11/4/CHEMI/HP2/ENG/TZ0/09.b

State the IUPAC names of each of the compounds, D, E, F and G.

D:

E:

F:

G:

[2]
b.i.

State the reagents and reaction conditions used to convert D to E and D to F directly.

[2]
b.iii.

Discuss the volatility of E compared to F.

[3]
b.iv.

Markscheme

D: 4-methylpentan-1-ol;

Allow 4-methyl-1-pentanol.

E: 4-methylpentanal;

F: 4-methylpentanoic acid;

G: 4-methylpentyl ethanoate;

Allow 4-methylpentyl acetate.

Award [2] for all four correct, [1 max] for two or three correct.

Award [1 max] if all suffices correct but prefix (4-methyl or pent) not correct.

b.i.

For both reactions reagents:

named suitable acidified oxidizing agent;

Suitable oxidizing agents are potassium dichromate(VI)/K2Cr2O7 / sodium dichromate(VI)/Na2Cr2O7 / dichromate/Cr2O72– / potassium manganate(VII)/potassium permanganate/KMnO4 / permanganate/manganate(VII)/MnO4.

Accept H+/H2SO4 instead of sulfuric acid and acidified.

Allow potassium dichromate or sodium dichromate (i.e. without (VI)) or potassium manganate (i.e. without (VII).

Conditions:

distillation for D to E and reflux for D to F;

Award [1 max] if correct reagents and conditions identified for one process only.

b.iii.

Volatility:

E more volatile than F;

hydrogen bonding in carboxylic acid/F;

Accept converse argument.

b.iv.

Examiners report

Many candidates only scored one mark.

b.i.

Distillation often was not mentioned.

b.iii.

(iv) was very well answered.

b.iv.

Syllabus sections

Additional higher level (AHL) » Topic 20: Organic chemistry » 20.2 Synthetic routes

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