AQA Jun 2015 Paper 4 Q3

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do not write outside the box titration curves labelled e f g and h for combinations of different aqueous solutions of acids and bases are shown in figure all solutions have concentrations of mol dm figure ph ph volume cm volume cm ph ph volume cm volume cm a in this part of the question write the appropriate letter in each box from the curves e f g and h choose the curve produced by the addition of a i sodium hydroxide to cm of ethanoic acid a ii ammonia to cm hydrobromic acid a iii hydrochloric acid to cm of potassium hydroxide mark mark mark wmp jun chem do not write outside the box b table shows information about some acid base indicators table indicator ph range lower ph colour higher ph colour pentamethoxy red naphthyl red nitrophenol cresol purple violet red colourless yellow colourless yellow yellow purple b i which indicator in table could be used for the titration that produces curve e but not for the titration that produces curve f mark tick one box pentamethoxy red naphthyl red nitrophenol cresol purple b ii give the colour change at the end point of the titration that produces curve h when naphthyl red is used as the indicator mark b iii a beaker contains cm of a buffer solution at ph two drops of each of the four indicators in table are added to this solution state the colour of the mixture of indicators in this buffer solution you should assume that the indicators do not react with each other mark turn over wmp jun chem

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