Question

Predict the products of electrolysis in each of the following:

 (i) An aqueous solution of AgNO₃ with silver electrodes.

 (ii) An aqueous solution of AgNO₃with platinum electrodes. 

(iii) A dilute solution of H₂SO₄with platinum electrodes.

 (iv) An aqueous solution of CuCl₂ with platinum electrodes.  

Answer 1

(i) At cathode: The following reduction reactions compete to take place at the cathode. 

The reaction with a higher value of 

takes place at the cathode. Therefore, deposition of silver will take place at the cathode. At anode: 

The Ag anode is attacked by NO₃ ions. Therefore, the silver electrode at the anode dissolves in the solution to form Ag⁺.

 (ii) At cathode:

 The following reduction reactions compete to take place at the cathode. 

The reaction with a higher value of E^o takes place at the cathode. Therefore, deposition of silver will take place at the cathode.

 At anode: 

Since Pt electrodes are inert, the anode is not attacked byNO₃  ions. Therefore, OH- or NO₃ ions can be oxidized at the anode. But OH− ions having a lower discharge potential and get preference and decompose to liberate O₂.