A sample of phenol glycerol injection was diluted with water and an aliquot was taken and reacted with excess bromine generated from potassium bromide and potassium bromate solutions. The excess bromine remaining after reaction was reacted with potassium iodide and the liberated iodine was titrated with sodium thiosulphate. A blank titration was carried out where the same quantity of bromine was generated as was used in the titration of the diluted injection, potassium iodide was then added and the liberated iodine was titrated with sodium thiosulphate. From the following data calculate the percentage of w/v of the phenol in the injection. Weight of injection taken for analysis = 4.214 g. The sample is diluted to 100 ml with water and then 25 ml of the solution is analysed. The volume of 0.1015 M sodium thiosulphate required to titrate the XS bromine after reaction with the sample = 22.4 ml. The volume of 0.1015 M sodium thiosulphate required to titrate the bromine blank = 48.9 ml. Density of glycerol = 1.26. The equations of the reactions are given above.
