Determination Of Dissolved Oxygen

Determination of DO & BOD in a irrigate supply system system try out © KCl      http://hk.geocities.com/fatherofchemistry Objective            utilize volumetric analysis, the amount of dissolve group O (DO) in a water sample gage be found. On standing another sample for 5 days, the residuum amidst these two places is defined as biochemical atomic play 8 demand in 5 days (BOD5). The aquatic life needs certain amount of DO for survival, whereas the nurse 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 fou nd 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, alkaline KI, old-hat Na 2S2O3, starch solution Apparatus   Ã! ‚ Â Â Â Â Â  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 exclusively with water without trapping any publicise bubbles.          2.> To one of the volumetric flask, land about 1 cm3 of MnSO4 solution well under 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 dole out the precipitate uniformly.          4.> When the precipitates has...If you necessity to get a full essay, ensnare it on our website: BestEssayCheap.com

If you want to get a full essa y, visit our page: cheap essay