Kraanivee kareduse määramine tiitrimise teel
assess efficiency of the filter.
1. Pipette 100 cm3 of the softened water into the clean conical flask (NB! Rinse
pipette couple of times with a small amount of softened water), add ~5 cm3 of
a buffer solution and a pinch (~0,1 g) of indicator ET-00.
2. Prepare the burette with more dilute 0,005 M trilon-B solution and titrate
water as in part B of lab until the blue color appears.
3. Calculate the residual total hardness as in part B.
Results
A:
ml of 0,005M trilone B solution
1. 2,50
2. 2,45
3. 2,45
Avarage: 2,47ml
B:
ml of 0,025M trilone B solution
1. 6,85
2. 6,90
3. 6,85
Avarage: 6,87ml
C:
ml of 0,005M trilone B solution is 0
Practical calculation
A:
Based on the best coinciding titration results average, calculating carbonate
hardness according to the following formula:
2,47 cm 3 ×0,005 M × 1000 mol
−¿ mmol
mM , HCO =3 3
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