Chemistry 9701 · AS & A Level · Analytical techniques

Analytical techniques — practice question

The hydrocarbon is identified as either compound D or compound E, as illustrated in Fig. 7.1.
(a)[1]

Give the systematic IUPAC name of E.

(b)

The proton ($^1\text{H}$) NMR spectra for D and E are being compared. They are almost the same. Fig. 7.2 shows the proton ($^1\text{H}$) NMR spectrum of D.

(b(i))[1]

Suggest a suitable solvent for recording the spectrum shown in Fig. 7.2.

(b(ii))[1]

The proton ($^1\text{H}$) NMR spectrum of E is recorded twice, once before shaking with $\text{D}_2\text{O}$ and once afterwards. Describe any differences between the two spectra. Explain your answer.

(b(iii))[3]

Complete Table 7.1 for D's proton ($^1\text{H}$) NMR spectrum.

(b(iv))[1]

Compounds D and E can be told apart using carbon-13 NMR spectroscopy. State the number of peaks in each spectrum. The carbon-13 NMR spectrum of D has ............... peaks. The carbon-13 NMR spectrum of E has ............... peaks.

(c)

As shown in Fig. 7.3, compound D can be oxidised to compound F using alkaline $\text{KMnO}_4$ and then dilute acid.

(c(i))[1]

Write an equation for this reaction using the molecular formulae of D and F. This reaction gives F, water and carbon dioxide as products. Use $[O]$ to represent one atom of oxygen from the oxidising agent.

(c(ii))[3]

F reacts with excess $\text{SOCl}_2$ to produce compound G. G has molecular formula $\text{C}_8\text{H}_4\text{Cl}_2\text{O}_2$. When G reacts with ethane-1,2-diol, $\text{HOCH}_2\text{CH}_2\text{OH}$, a mixture of products is formed that includes J, with molecular formula $\text{C}_{10}\text{H}_8\text{O}_4$, and K, with molecular formula $\text{C}_{18}\text{H}_{12}\text{Cl}_2\text{O}_6$. Draw the structures of compounds G, J and K in Fig. 7.4.

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