Analysis of 2 commercial brands Essay

Topic Analysis of 2 commercialised brands of blanching agenting termination & a determination of the best buy Introduction Sodium chlorate(I) forms the floor of most commercial de touches. The amount present in bleaching agenting radical sewer be determined by a tawdrinesstric technique. In this experiment, sodium chlorate(I) fight backs with profusion potassium iodide in the presence of stinging to liberate. The unity is titrated against measuring stick sodium thiosulphate upshot.Chemicals Bleach solution , 0.1 M Na2S2O3 ,1 M H2SO4 , KI , amylum indicatorProcedures 1. Determine the total volume of bleach in the commercial bottles permitd. Note the brand name, volume & price of each sample.2. Pipette 25 cm3 bleach solution into a 250 cm3 volumetric flask. Make up to the hold in & mix well.3. Pipette 25 cm3 of this solution into a conical flask. institute 10 cm3 KI solution & 10 cm3 1 M sulphuric acid.4. Titrate this mixture against the standard sodium thiosulp hate solution provided. Add stiffen indicator when the solution become pale yellow.5. Record your results and calculate the metre of the orginal bleach solution.6. Determine which bleach has the lowest price per bulwark of veritable bleach.Results provoker A = ___________KAO_____________ target B = _________Best Buy____________ mickle = ___________1.5L______________ Volume = ____________2L_______________ hurt = _______$12.9 / Bottle____________ Price = ________$10.9 / Bottle____________Mole = _________0.753 Mol_____________ Mole = ___________1.152 Mol ___________$/bulwarke = _______$17.13 / Mol ___________ $/bulwark = __________$9.46 / Mol__________Best buy is ________ Best Buy___________Tit symmetryn of Brand A against the standard sodium thiosulphate solutionTitration1234Final burette indication (ml)31.7035.7027.8032.20Initial Burette Reading (ml)2.909.804.408.30Volume of titrant (ml)28.8025.9025.4023.50Mean volume of titrant (ml) = __(25.90+25.40+23.50)3 = 25.1 ml__Calcula tionThe Result Of Brand ASodium chlorate(I) reacts with excess potassium iodide in the Bleaching solution, which is a acid medium. Iodine solution produced. interest equivalence 2H+-(aq) + OCl(aq) + 2I(aq) Cl(aq) + I2-(aq) + H2O-(l)Secondly, the unity solution is titrated with sodium thiosulphate solution pastime equation I2(aq) + 2 S2O32- (aq) S4O62- (aq) + 2 I-(aq)The metre of Na2S2O3 = 0.1M matter of mole of S2O3- reacted with I2 = Molarity X Volume= 0.1 X (25.11000) = 0.00251 molThe Mole ratio of Na2S2O3 I2= 21 list of moles of I2 reacted with S2O3-= (12) X 0.00251 mol= 0.001255 molThe Mole ratio of NaOCl I2= 11 account of moles of NaOCl used in the titration= I2= 0.001255 molNumber of moles of NaOCl in the 250ml volumetic flask= 0.001255 mol X 10= 0.01255 molNumber of moles in 1.5L bleach solution= 0.01255 mol 25 X 1500= 0.753 molPrice of OCl- per mole in brand A= $12.9 0.753mol= $17.13 / molResults Titration of Brand B against the standard sodium thiosulphate solutionTi tration1234Final Burette Reading (ml)30.9032.831.9035.20Initial Burette Reading (ml)2.103.903.306.90Volume of titrant (ml)28.828.9028.6028.90Mean volume of titrant (ml) = __(28.90+28.60+28.90)3 = 28.8 ml__CalculationThe Result Of Brand BSodium chlorate(I) reacts with excess potassium iodide in the Bleaching solution, which is a acid medium. Iodine solution produced.Following ionic equation 2H+-(aq) + OCl(aq) + 2I(aq) Cl(aq) + I2-(aq) + H2O-(l)Secondly, the unity solution is titrated with sodium thiosulphate solutionFollowing ionic equation I2(aq) + 2 S2O32- (aq) S4O62- (aq) + 2 I-(aq)The Molarity of Na2S2O3 = 0.1MNumber of mole of S2O3- reacted with I2 = Molarity X Volume= 0.1 X (28.81000)= 0.00288 molThe Mole ratio of Na2S2O3 I2= 21Number of moles of I2 reacted with S2O3-= (12) X 0.00288 mol= 0.00144 molThe Mole ratio of NaOCl I2= 11Number of moles of NaOCl used in the titration= I2= 0.00144 molNumber of moles of NaOCl in the 250ml volumetic flask= 0.00144 mol X 10= 0.0144 molNu mber of moles in 2L bleach solution= 0.0144 mol 25 X 2000= 1.152 molPrice of OCl- per mole in brand B= $10.9 1.152 mol= $9.46 / molQuestions 1. Why mustiness(prenominal) the KI be present in excess ? If less than the condition quantity of KI is added, what effect entrust this digest on the results ?The bleach solution ensure sodium chlorate(I),which have ions OCl-.We can prepare the iodine solution by adding the sodium chlorate(I) to potassium iodide in a acidic medium. At first, the sodium chlorate(I) Is the limiting agent. When we add the excess potassium iodide into the bleach solution. Not only it will not effect the result, but similarly the calculation can be more accurate. All the ions OCl- can be completely reacted.In addition, Iodine solution is only slightly meltable in water but it is very soluble in the solution, which contain I- ions.2. What is the function of the sulphuric acid ?The function of sulphuric acid is provide a acidic medium containing excess iodi de to ionizes the iodine solution to triiodide ions. We must know that the Brown colour of iodine solution is cause for the triiodide ions(I3-).This colour in observation of titration is very important.3. Bleaching solutions may deteriorate for 2 reasons (a) react with carbonic acid gas in the air according to the equation 2 OCl- + CO2 CO32-+ H2 + Cl2(b) what is the other reason ?It must be effected by light. It is because the The hypochlorite ions OCl-( will be decompose quickly under light Following equation2NaOCl 2NaCl + O2, .While losing some OCl- ions, the result in calculation will not be accurate4. What should the starch indicator not be added too wee ?The starch solution turns the iodine to blue black because of the formation of starch-iodine labyrinthine. Also, the complex is not reversible when the concentration of iodine is high. If we add the starch solution early, the attraction of starch molecules and iodine molecules will attract so strongly. Although we have add standard sodium thiosulphate solution, but we can not do completely finish the real result of titration and effecting the calculation. The above-mentioned tell us that the starch solution should be added when only a few of iodine solution left, near the end point of the titration.ConclusionThe bleach solution of brand B is the best buy.