Compound S is used in food flavourings. A possible synthesis of S is shown in Fig. 4.1. P HBr reaction 1 Q KCN in ethanol reaction 2 R CN H+(aq) reaction 3 S COOH [Figure 4.1]

1. (a)P, Q, R and S show stereoisomerism. Complete Table 4.1 by identifying with a tick (✓) the type of stereoisomerism that each molecule shows. The type of stereoisomerism shown by Q is given. Table 4.1 molecule geometrical isomerism optical isomerism P Q ✓ R S[2]
2. (b)(i)Give the structural formula of Q.[1]
3. (b)(ii)Name the mechanism in reaction 2.[1]
4. (b)(iii)Complete the equation for reaction 3. R is represented as C4H9CN. C4H9CN +[1]
5. (c)(i)Compounds S and T react to form organic compound U, which has a single functional group. S + T COOH Table 4.2 shows some data from the mass spectrum of U. Table 4.2 peak M+ [M+1]+ relative abundance 7.2 0.55 U + H2O Use the data from Table 4.2 to show that U contains 7 carbon atoms. Show your working.[2]
6. (c)(ii)Fig. 4.2 shows the infrared spectrum of U. [Figure 4.2] Use Fig. 4.2 and Table 4.3 to identify the functional group present in U. Explain your answer fully. functional group explanation[2]
7. (c)(iii)T also has a single functional group. Use the information in (c)(i) and your answer to (c)(ii) to identify T and U. Draw the structures of T and U in the boxes. T U[2]

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