This document describes the titration process for determining the molarity of a permanganate solution and the concentration of commercial bleach and vinegar.
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[...] Titration : The sodium thiosulfate solution is then added dropwise to the bleach sample until the blue color of the starch disappears, indicating that all the diiodine has been consumed by the reaction with sodium thiosulfate. 5. Calculation of the concentration of bleach : From the volume of titrated sodium thiosulfate solution and its known concentration, as well as the volume of titrated bleach, it is possible to calculate the concentration of bleach per unit volume. This method allows for the indirect determination of the concentration of bleach by using a known chemical reaction between bleach and sodium thiosulfate, with an added indicator to facilitate the detection of the reaction's equivalence point. [...]
[...] Volume of dosed vinegar solution and material used for sampling: Vv=25mL A graduated pipette is used for this specific volume (25 mL). Then, a beaker is used to contain the vinegar sampled. It is essential to handle the material with care to obtain precise measurements. Volume of sodium hydroxide solution discharged: Test Vb=43.8-0.6=43.2 mL / Test Vb=43.6-0.4=43.2 mL / Test Vb=43.7-0.8=42.9 mL Volume retained: Vb= 43.2 mL (average of the 2 retained tests) Calculation of the molarity of commercial vinegar: CbVb=CaVv So Ca=CbVb/Vv=0.4936*43.2/25=0.8529 mol/L Calculation of the commercial mass titre: M(CH3COOH)=60g/mol Cm=M*Ca=60*0.8529=51.174g/L Density of commercial vinegar: m =159,428-134,345=25,083 g density =m/V=25,083/0,025=1003.32 g/L Calculation of the mass centesimal composition of vinegar : 51,174/1003,32*100=5,10% This result is consistent with the 5th shown. [...]
[...] Volume of sodium thiosulfate solution run: Test Vt=19.30mL Test Vt=19.25 mL Test Vt=19.35 mL Volume retained (average of VT=19.30 mL Calculation of the molarity of the hypochlorite ion in commercial bleach solution: [...]
[...] Preparation of the sodium thiosulfate solution A solution of sodium thiosulfate of known concentration is prepared. This solution will serve as a titrant reagent to react with bleach. 2. Preparation of the bleach sample : Bleach is diluted to a concentration where it can be easily titrated with the sodium thiosulfate solution. Usually, a known quantity of bleach is diluted in a determined volume of water. 3. Addition of indicator : An appropriate indicator is added to the bleach sample. [...]
