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 name for E.

(b)

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

(b(i))[1]

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

(b(ii))[1]

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

(b(iii))[3]

Complete Table 7.1 using the proton ($^{1}\text{H}$) NMR spectrum of D.

(b(iv))[1]

Compounds D and E can be told apart by 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)

Compound D is oxidised to compound F by alkaline $\text{KMnO}_4$ followed by dilute acid, as shown in Fig. 7.3.

(c(i))[1]

Write an equation for this reaction using molecular formulae for D and F. The products of this reaction are F, water and carbon dioxide. Use $[\text{O}]$ to represent one atom of oxygen from the oxidising agent.

(c(ii))[3]

F reacts with an excess of $\text{SOCl}_2$ to form compound G. The molecular formula of G is $\text{C}_8\text{H}_4\text{Cl}_2\text{O}_2$. G reacts with ethane-1,2-diol, $\text{HOCH}_2\text{CH}_2\text{OH}$, to form a mixture of products that includes compounds J, molecular formula $\text{C}_{10}\text{H}_8\text{O}_4$, and K, 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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