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Alt 03.12.2009, 13:19   #3   Druckbare Version zeigen
Nobby Männlich
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AW: Iodometrische Bestimmung von Cu2+

Wir bestimmen Kupfer auch mit Thiocyanat.

Vermute mal nach folgender Gleichung;

2 Cu2+ + 2 I- + 2 SCN- => 2CuSCN + I2


Iodometric titration – Redox titration (Potentiometic titration).

Reagents required*:

Potassium iodide-potassium thiocyanate solution (50 g/l of KI and 200 g/l of KSCN in DI water)
Sodium thiosulfate standard solution 0.1 M (0.1 N)
Starch solution 1 % w/w (aqueous)
Sulfuric acid 5 M (10 N, 280 ml/l of H2SO4 98 % w/w, d = 1.84 g/cm³)

Be sure to observe all local regulations concerning the permitted limits for pollutants, including the general regulations for hazardous materials!


25.0 ml** of the sample will be pipetted into a 250 ml Erlenmeyer flask and mixed with
25 ml of DI water,
20 ml of 5 M sulfuric acid and
20 ml of KI-KSCN solution.
2 ml of starch solution will be added. Then titrate with
0.1 M sodium thiosulfate standard solution until the blue color has completely disappeared.

The volume in ml of 0.1 M sodium thiosulfate standard solution*** used, multiplied by 5.08, gives the content of Copper Solution ml/l.
Vena lausa moris pax drux bis totis
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