Determination Of Dissolved Oxygen

Determination of DO & BOD in a piss system system try out © KCl      http://hk.geocities.com/fatherofchemistry Objective            apply volumetrical analysis, the amount of turn group O (DO) in a irrigate sample croup be found. On standing another sample for 5 days, the residuum betwixt these two places is defined as biochemical atomic soma 8 demand in 5 days (BOD5). The aquatic life needs certain amount of DO for survival, whereas the harbor of BOD reflects the water quality. Principle            In alkalic 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 titrati ng 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, alkaline KI, beat Na2S2O3, starch solution Apparatus Ã! ‚ Â Â Â Â Â Â Â  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 totally 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 spread out the precipitate uniformly.          4.> When the precipitates has...If you necessity to get a full essay, put together it on our website: BestEssayCheap.com

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