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Grade 12th passInorganic Chemistry

measurement of electrode potential of zinc using calomel electrode

Profile image of DEVIKA P J
7 Years agoGrade 12th pass
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Profile image of Arun
7 Years ago

Prepare 1 M (or any concentration as you required) zinc sulphate solution then immerse zinc electrode in it and connect it to saturated calomel electrode (standard electrode potential at 25 oC is 0.2422 V) immersed in KCl solution by a salt bridge (just use filter paper soaked in KCl). measure the potential difference between the two by connecting tw SCE and Zn electrode to a potentiometer (Voltmeter) measure the potential difference. Let us assume the potentiometer displays 0.9992 V then the Electrode potential of Zn is 0.9992 - 0.2422 = 0.75 V but most importantly the temperature as well as concentration factors are affect the SEP. If you have different concentration other than 1 M or temp. other than 25 oC, then use the Nernst equation, through which you can estimate single electrode potential exactly.

PS: Here Zn undergoes oxidation when connected to reference electrode (SCE) and dont forget to use negative sign before as -0.75V.