quantify caffeine in the Proplus tablets. The following procedure was used to prepare the samples to be analysed: - Stock caffeine solution contained 500mg of caffeine in 100cm3 of ethyl acetate. - Internal standard (IS) solution contained 0.25cm3 of hexadecane in 100cm3 of ethyl acetate. - Ten Proplus 2 tablets were weighed and crushed and an amount equivalent to the weight of two tablets was added to 50cm3 of ethyl acetate in a volumetric flask. 5cm3 of this solution was added to 4cm3 of internal standard solution and made up to 10cm3 with ethyl acetate in a volumetric flask. (i) Calculate the concentration of caffeine in each of the FIVE standards (mg dm3) (ii) Calculate the ratio of the integration of I.S. to caffeine for each of the FIVE standards and the tablet solution. (iii) Using the data, plot an appropriate graph and use it to calculate the amount of caffeine per tablet in the Proplus (3) preparation. [15 marks]