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Question 4 20 marks Sodium montmorillonite is an anionic hydrophilic clay. You wish to make the clay hydrophobic by adsorbing a monolayer of a cationic surfactant (molecular weight 300 g.mole-1), which adsorbs on the clay at a level of 0.5 mg/m². The thickness of a sodium montmorillonite plate (montmorillonite is a clay) is 0.97 nm and the density of sodium montmorillonite is 2800 kg.m-³ a) Calculate the maximum amount of surfactant required per gram of sodium montmorillonite stating any assumptions which you make. 10 marks b) On average how far apart would these surfactant molecules be? (Note that the counterion has not been included in the quoted molecular weight of the surfactant). 10 marks