Easy to Pharmaccy & learnt. I Sem. B.Pharm - 1st Year

2. ▪ Potentiometric method of analysis are based on measurement of potential electrochemical
cells under condition of zero current..
First quantitative potentiometric applications appeared soon after the formulation of Nernst
equation..
Potentiometry the potential of an electrochemical cell is measured under the static
condition..
Because no current flows while measuring a solution potential , it’s composition unchanged..

3. ▪ To determine difference between sensing electrode and reference electrode..
▪ Sensing electrode : cathode which undergoes reduction..
▪ Reference electrode: anode which undergoes oxidation..
▪ Separation of 2 electrode to prevent redox from occurring involuntarily on surface of one electrode..
▪ Salt bridge contain inert electrolyte such as KCl -
-connects two half-cells..
The movements of ions in the salt bridge completes the-
-electrical circuit.
ECELL Ec – Ea + Eij

4. ▪ It has a standard potential on its own and it’s potential does not change to solution it is
dipped..
▪ Always treated as the anode electrode..
▪ Examples- [a]. Standard hydrogen electrode.
▪ [b]. Saturated calomel electrode.
▪ [c]. Silver-silver chloride electrode.

5. ▪ Defined as potential that is developed between hydrogen gas absorbed on the Pt metal and
H+ of the solution..
▪ It is used for-
▪ Determination of electrode potential ..
▪ Determination of pH of the solution..

6. ▪ Widely used because simple , inexpensive , very stable an non –toxic..
▪ Mainly used with saturated potassium chloride electrolyte.
▪ Advantages – easy to use ..

7. ▪ Contains of an inner jacket and outer sleeve..
▪ Inner jacket has wire contacts with Hg and plugged with mixture of calomel Hg2Cl2 and
KCl.
▪ Outer sleeve has crystals of KCl and porous plug of asbestos..
▪ Application – pH measurement , general aqueous electrochemistry..
▪ Advantages - construction and stability of potential..

8. ▪ Advantages over other electrodes for pH measurement . It’s potential does not effected
by the presence of oxidizing and reducing agent..
▪ It operate over a white pH range..

9. ▪ Metal electrodes are system that use specific metal electrodes as the electrodes in an
electrochemical measurement..
▪ Ecell = Eind. + Eref + Ej
▪ There are two kinds of metal electrodes..
▪ [a].The electrodes potential responds directly in relationship to the concentration of the
metal ion ..
▪ cu 2+ + 2e- = cu
▪ [b]. Metal analyte ion is equilivrium with the target analyte..
Cu2+ + 2l- = cul2.

10. ▪ Clinical chemistry.
▪ Environmental chemistry.
▪ Agriculture.
▪ Detergent manufacturing.
▪ Food processing.

11. ▪Thank you –
▪ Rahul pal’s