Determination Of Dissolved Oxygen

Determination of DO & BOD in a pissing system system try out © KCl      http://hk.geocities.com/fatherofchemistry Objective            employ volumetric analysis, the amount of fade out group O (DO) in a water supply sample spate be found. On standing another sample for 5 days, the residuum surrounded by these two places is defined as biochemical atomic snatch 8 demand in 5 days (BOD5). The aquatic life needs certain amount of DO for survival, whereas the take to be of BOD reflects the water quality. Principle            In alcalescent solution, dissolved oxygen will oxidize manganese(II) into manganese(III):                         4Mn2+(aq)   +   8OH-(aq)   +   O2(aq)   +   2H2O(l)   â†Â Â  4Mn(OH)3(s)               The amount of DO can be found by titrating the iodine produced from potassium iodide by manganese(III) with atomic number 11 thiosulphate:                        2Mn(OH)3(s)   +   2I-(aq)   +   6H+(aq)   â†Â Â  2Mn2+(aq)   +   I2(aq)   +   6H2O(l)                          I2(aq)   +   2S2O32-(aq)   â†Â Â  2I-(aq)   +   S4O62-(aq) Chemicals          water sample, MnSO4, conc.

H2 SO4, alkaline KI, meter Na2S2O3, starch sol! ution Apparatus          titration apparatus, pipette, 250cm3 volumetric flask x2, beaker, droppers, magnetised stirrer, white tile Procedure          1.> Collect a water sample with two 250cm3 volumetric flasks. Remember to fill the flasks all with water without trapping any publicise bubbles.          2.> To one of the volumetric flask, land about 1 cm3 of MnSO4 solution well infra the issue with a dropper.          3.> Similarly, introduce about 1 cm3 of alkaline KI solution to the same flask. Be sure that no air becomes entrapped and then invert the stopped                flask to select the precipitate uniformly.          4.> When the precipitates has...If you necessity to get a full essay, ball club it on our website: OrderCustomPaper.com

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