Answer all the questions in the spaces provided. (a) An alkene, a carboxylic acid and a ketone, all of similar volatility, are mixed together. The mixture is then analysed by gas chromatography. The gas chromatogram produced is shown. [Figure 1.0] The separation of the three compounds depends on their relative solubilities in the liquid stationary phase. The liquid stationary phase is an alkane.

1. (a)(i)Complete the table to suggest which compound in the mixture is responsible for each peak J, K and L. Explain your answer by reference to the intermolecular forces of each compound. peak organic compound explanation J K L[2]
2. (a)(ii)A student calculates the areas underneath the three peaks in the chromatogram. peak J K L area/mm² 46 18 28 The area underneath each peak is proportional to the mass of the respective compound. Calculate the percentage by mass in the original mixture of the compound responsible for peak K. % of mixture responsible for peak K =[1]
3. (b)Chlorobenzene can be prepared from benzene as shown. [Figure 1.1] Aluminium chloride, AlCl3, catalyses this reaction.
4. (b)(i)Write an equation to show how AlCl3 generates the electrophile needed in this reaction.[1]
5. (b)(ii)Draw the mechanism of the reaction between this electrophile and benzene to form chlorobenzene. Include all relevant curly arrows and charges.[4]
6. (b)(iii)Write an equation to show how the catalyst is regenerated.[1]
7. (c)(i)Catalysts can be heterogeneous or homogeneous. Explain what is meant by a homogeneous catalyst.[1]
8. (c)(ii)Complete the table by placing one tick (✔) in each row to indicate the mode of action of the catalyst in each reaction. heterogeneous | homogeneous Rh in the removal of NO2 from exhaust gases of cars Fe3+ in the I-/S2O32- reaction[1]

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