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XX
Release 05/04
Instructions for the Preparation of Standard Solutions
Standard solution of bromine
acc. to DIN EN ISO 7393
Preparation of a KlO
3
stock solution:
Dissolve 1.005 g of KlO
3
in 250 ml of distilled
water in a calibrated or conformity-checked
1000-ml volumetric flask. Subsequently make up
to the mark with distilled water.
▼
Preparation of a KlO
3
/Kl standard solution:
Transfer 8.90 ml of the KlO
3
stock solution to a
calibrated or conformity-checked 1000-ml
volumetric flask, add approx. 1g of Kl and make
up to the mark with distilled water.
1 ml of this solution is equivalent to 0.020 mg
of bromine.
▼
Preparation of the bromine standard solution:
Pipette 10 ml KlO
3
/Kl standard solution into a
calibrated or conformity-checked 100-ml
volumetric flask, add 2.0 ml of H
2
SO
4
0.5 mol/l,
leave to stand for 1 min, and then add NaOH 2
mol/l dropwise (approx. 1 ml) until the solution
just loses its colour. Subsequently make up the
solution to the mark with distilled water.
The concentration of the solution is 2.00 mg/l
bromine.
▼
Stability:
The KlO
3
stock solution remains stable for 4
weeks when stored in a cool place. The KlO
3
/Kl
standard solution can be used for 5 hours when
stored in a cool place. The dilute bromine
standard solution is not stable and must be used
immediately.
▼
Reagents required:
1.02404.0100 Potassium iodate, volum. standard
1.05043.0250 Potassium iodide GR for analysis
1.09072.1000 Sulfuric acid 0.5 mol/l
1.09136.1000 Sodium hydroxide solution 2 mol/l
1.16754.9010 Water GR for analysis
Standard solution of acid capacity
Preparation of a standard solution:
A sodium hydroxide solution of 0.1 mol/l
(corresponds to 100 mmol/l) is used.
Further investigational concentrations may be
prepared from this stock solution by diluting
accordingly.
▼
Stability:
When stored in a cool place (refrigerator), the
diluted investigational solutions remain stable
for one week.
▼
Reagents required:
1.09141.1000 Sodium hydroxide solution
0.1 mol/l
1.16754.9010 Water GR for analysis