Determination Of Dissolved Oxygen

Determination of DO & BOD in a irrigate system system try out © KCl      http://hk.geocities.com/fatherofchemistry Objective            using volumetrical analysis, the amount of fade out group O (DO) in a wet sample cigaret be found. On standing another sample for 5 days, the residuum surrounded by these two places is defined as biochemical atomic anatomy 8 demand in 5 days (BOD5). The aquatic life needs certain amount of DO for survival, whereas the rate of BOD reflects the water quality. Principle            In alkaline 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 foun d 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.

H2SO4, a lkaline KI, ideal Na2S2O3, starch solution ! Apparatus          titration apparatus, pipette, 250cm3 volumetric flask x2, beaker, droppers, magnetized stirrer, white tile Procedure          1.> Collect a water sample with two 250cm3 volumetric flasks. Remember to fill the flasks on the whole with water without trapping any publicise bubbles.          2.> To one of the volumetric flask, land about 1 cm3 of MnSO4 solution well beneath 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 break the precipitate uniformly.          4.> When the precipitates has...If you necessity to get a full essay, nightclub it on our website: BestEssayCheap.com

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