(a) In the electrophilic substitution of arenes, different substituents can direct to different ring positions. (i) Describe the directing effect of the –NO2 group. Explain your answer. [1] (ii) The nitration of arenes uses a mixture of concentrated HNO3 and concentrated H2SO4 to generate the NO2+ electrophile. Write an equation for the formation of the NO2+ electrophile. [1] (b) Carbon-carbon bond formation is an important reaction in organic synthesis. Fig. 8.1 shows the synthesis of compound Q from benzene in two reaction steps. [Figure 8.1] (i) Draw the structure of compound P in the box in Fig. 8.1. [drawing box] [1] (ii) Suggest reagents and conditions for reactions 1 and 2 in Fig. 8.1. reaction 1 reaction 2 [2] (c) Separate samples of C6H5Br and C6H5CH2Br are added to warm AgNO3(aq). State the expected observations, if any. Explain your answer. C6H5Br with AgNO3(aq) C6H5CH2Br with AgNO3(aq) explanation [3] (d) Acyl bromides, RCOBr, react readily with H₂O. The mechanism of this reaction is similar to that of the reaction of H₂O with acyl chlorides, RCOCl. (i) Name the mechanism of this reaction. [1] (ii) Complete the mechanism in Fig. 8.2 for the reaction of RCOBr with H2O. Include all relevant lone pairs of electrons, curly arrows, charges and dipoles. Draw the structure of the intermediate. [Figure 8.2] [4]