3 marks b Determine the pH of a buffered solution prepared by mixing 100.0 mL of 0.100 mol L-1 benzoic acid solution with 50.0 mL of 0. Determine the pH of a 0.0100 mol L-1 solution. Each mL of 1 N sulfuric acid is equivalent to 17.03 mg of NH 3. Transcribed image text: Question 35 a Dilute ammonia solutions are often used to treat mosquito bites since it neutralises the acid injected by the mosquitos. Perform a blank determination (see Residual Titrations under Titrimetry 541 ). Titrate the excess acid with 1 N sodium hydroxide VS, using methyl red TS as the indicator. Insert the stopper, mix, and again weigh to obtain the weight of the specimen. Hold the pipet just above the surface of the 1 N sulfuric acid VS in the conical flask, and transfer about 2 mL of the Solution into the flask. Insert a graduated 10-mL measuring pipet into the cooled Solution, allow the liquid to rise in the pipet without vacuum, remove the pipet, wipe off adhering liquid, and discard the first mL of the Solution permitted to run from the pipet. Weigh accurately a glass-stoppered, 125-mL conical flask containing 35.0 mL of 1 N sulfuric acid VS. Transfer quickly a portion of Solution to a stoppered, thick-walled container (a pressure bottle is suitable) to obtain a column height of about 20 cm, insert the stopper, and cool the container and contents to 10 or lower.
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