Metrohm 794 Basic Titrino - Manual (Page 15)

2.4 Tutorial
794 Basic Titrino
11
2.4.2 Development of a method, titration of an acid
Selection of the mode
<MODE>
<ENTER>
4 × <SELECT>
• Press <MODE> repeatedly until "DET" appears in
the display. For a description of the DET mode see
page 25.
• Confirm "DET" with <ENTER>
• Now select the measured quantity: Press
<SELECT> repeatedly until "pH" appears again in
the display.
Confirm the measured quantity "pH" with
<ENTER>.
You are now ready to titrate.
For the titration put a Exchange Unit with c(NaOH) = 0.1 mol/L on the Titrino and rinse
the tubing and the buret Tipp with <DOS>. Fill the buret again with <STOP/FILL>.
Plug a combined pH glass electrode into measuring input 1 (Ind I).
Pipette 2 mL c(HCl) = 0.1 mol/L into your titration vessel, dilute with ca. 20 mL dist. water.
Put a magnetic stirrer in the titration vessel and place buret tip and electrode in the probe,
see page 157 for their arrangement.
Start the stirrer and press <START>
During the titration the first line of the display shows the current measured value and the
volume already dispensed:
As soon as the instrument has found an equivalence point, this is shown on the second
line:
Let the titration continue for a short while, e.g. until ca. pH 11.50. Now stop it with
<STOP>.
The first line now shows the mode "DET pH" and the name of the chosen method (here
"********" because this method has not been saved under a own name until now). Of
interest is the second line, which shows the equivalence point found.
mode
mode DET
DET pH ********
DET: pH
DET pH ********
pH 3.02 0.351 ml
pH 7.64 2.083 ml
EP1
DET pH ********
EP1 2.083 ml pH 7.64