Analysis of Spinning Bath with Potentiometric Method

Analysis of Spinning Bath With Potentiometric Method

Reagents
c(NaOH) = 0.1 mol/L; D0

Sample
0.1 mL c(ZnSO4) ≅ 0.1 mol/L in c(H2SO4) ≅ 1 mol/L
25 mL dist. water

Electrodes
6.0232.100 combined pH glass electrode; input 1

Remarks
• EP1: H₂SO₄ + 2OH^- ⇒ SO4 ^2- + 2H₂O

EP2: Zn²⁺ + 2 OH^- ⇒ Zn(OH)₂ (s)

Calculations:
H2SO4 = concentration of H2SO4 in g/L
ZnSO4 = concentration of ZnSO4 in g/L
C01 = concentration of titrating agent (0.1 mol/L)
C02 = molecular mass of H2SO4 (98.08 g/mol)
C03 = molecular mass of ZnSO4 (161.23 g/mol)
C04 = factor for “normality“ (2)
• For automatic curve output add in , >report “curve“.

Literature
Metrohm's Teachware on CD-ROM

Method documentation

'pa
751 GPD Titrino...15215...751.0010
SET pH...Spinning
parameters
>SET1
EP at pH...5.50
dynamics...3
max.rate ...5 ml/min
min.rate...1 μl/min
stop crit:...drift
stop drift ...20 μl/min
>SET2
EP at pH...9.50
dynamics...4
max.rate...1 ml/min
min.rate ...1 μl/min
stop crit:... drift
stop drift ... 20 μl/min
>titration parameters
titr.direction:...auto
pause 1... 0s
start V: ...OFF
pause 2...0s
extr.time... 0s
dos.element:...internal D0
meas.input:...1
temperature...25.0 °C
time interval...2s
>stop conditions
stop V:... abs.
stop V...99.99 ml
filling rate...max. ml/min
>statistics
status:...OFF
>preselections
conditioning:...OFF
req.ident:...OFF
req.smpl size:...OFF
activate pulse:...OFF
------------
'fm
751 GPD Titrino 15215 751.0010
SET pH...Spinning
>calculations

H₂SO₄=EP1*C01*C02/C04/C00;2;g/l
ZnSO₄=(EP2-EP1)*C01*C03/C04/C00;2;g/l

C00= 0.1
C01= 0.1
C02= 98.93
C03= 161.23
C04= 2
------------
'fr
751 GPD Titrino 15215 751.0010
pHc(init) 2.22 SET pH Spinning
smpl size 0.1 ml
EP1 2.011 ml 5.61
EP2 2.245 ml 9.53
H2SO4 99.47 g/l
ZnSO4 18.86 g/l
============
'cu
751 GPD Titrino 15215 751.0010
SET pH Spinning
20.0 s/div dV=0.5 ml/div