Hanna Instruments HI 902 Color, Quick Start Manual

Page: 205 / 248

Method ID: HI0200EN
0.02 M Silver Nitrate Titrant Concentration
Titrator Application Methods: General Methods - r. 2.3
Description :
Method for the standardization (titer determination)
of 0.02M Silver Nitrate (AgNO
3
) titrant solution
against Sodium Chloride (NaCl). The results are
expressed in
mol/L (M).
Reference:
AOAC Official Methods of Analysis, Official Method
941.18
Electrode :

HI 4015 Silver Sulfide Half-cell ISE

HI 5315 ISE Reference Electrode

HI 7662-T Temperature Probe
- or -

HI 4115 Silver Sulfide Combination ISE

HI 7662-T Temperature Probe
Reagents :

HI 70448 0.02N Silver Nitrate Solution (1 L)

HI 70427 1.5M Nitric Acid Solution (500 mL)

HI 70406 Sodium Chloride (20 g)

HI 70436 Distilled Water (1 gal)
Other Accessories :

HI 7072 Electrode Fill Solution (4*30 mL)

150-mL Glass Beakers

100-mL Class-A Volumetric Flask

5-mL Class-A Volumetric Pipette

Analytical Balance with a minimum resolution of
0.0001g is recommended
Procedure :

Connect the silver sulfide ISE, temperature probe,
and reference electrode (if needed) to the titrator.

Press “
Select Method
” from the main screen. Use
the arrow keys to highlight „HI0200EN 0.02M
AgNO3 Titr. Conc.‟ and press “
Select
”.

Install a 25-mL burette filled with 0.02M silver
nitrate solution (HI 70448) on pump-one and verify
that no air bubbles are present in the burette or
tubing. If necessary prime until all air has been
removed completely.

Crush approximately 2 grams of sodium chloride
(HI 70406) and dry it for 2 hours at 120°C. Cool to
room temperature in a desiccator.

Weigh 0.20 g of dried sodium chloride with an
accuracy of 0.0001 g. Transfer the salt to a 100-
mL volumetric flask. Add approximately 80 mL of
distilled water and mix. Dissolve completely before
bringing to volume.

Use a class-A volumetric pipette to transfer
exactly 5.00 mL of prepared standard solution to a
150-mL glass beaker and add distilled water to the
100-mL mark on the beaker.

To the beaker add 10 mL of 1.5M nitric acid (HI
70427).

Place the beaker under the stirrer assembly and
immerse the electrodes and stirrer. Ensure that
the reference junction of the ORP electrode is 5-6
mm below the surface. If necessary add extra
distilled water.

Press “
Start
”. You will be prompted to enter the
analyte size (weight of NaCl). Use the numeric
keypad to enter the exact weight and press
“
Enter
” to start the analysis.

At the end of the titration, after detection of the
equival
ence point, „titration completed‟ will appear
with the titrant concentration. The result is
expressed in
M (mol/L) of silver nitrate .

Remove the electrode and stirrer from the sample
and rinse them thoroughly with distilled water.

Record the result (titer concentration).
NOTE: For optimal accuracy repeat this procedure a
minimum of three times and calculate the mean
value.
For methods utilizing 0.02M AgNO
3
titrant
solution, follow the steps below to enter the
titer/standardized value.

Select the method utilizing 0.02M AgNO
3
.

Select „Method Options‟ from the main screen.

Using the arrow keys, highlight „Titrant Conc.‟ and
press “Select”.

Use the numeric keypad to enter the standardized
(titer) value of the titrant then press „Accept‟.

Press „Escape‟ to exit the Method Options screen
and select „Save Method‟ option.
Method Parameters :
Name: 0.02M AgNO3 Titr. Conc.
Method Revision: 2.3
Titration Type: Standard Titration
Analog Board: Analog 1
Stirrer Configuration: Stirrer 1
Pump Configuration:
Titrant Pump: Pump 1
Dosing Type: Dynamic
min Vol: 0.030 mL
max Vol: 0.500 mL
delta E: 5.000 mV
End Point Mode: mV 1EQ point, 1st Der.
Recognition Options:
Threshold: 100 mV/mL
Range: No
Filtered Derivatives: Yes
Pre-Titration Volume: 6.000 mL
Pre-Titration Stir Time: 0 sec
Measurement Mode: Signal Stability
delta E: 1.0 mV
delta t: 1.5 sec
t-min wait: 2 sec
t-max wait: 20 sec
Electrode Type: Silver Sulfide
Blank Option: No Blank
Calculations: Stdz. Titrant by Weight
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