Question

Predict the products of electrolysis in each of the following: 

(i) An aqueous solution of AgNO₃ with silver electrodes 

(ii) An aqueous solution AgNO₃ with platinum electrodes 

(iii) A dilute solution of H₂SO₄ with platinum electrodes 

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

Answer 1

Answer: We have

(i) AgNO³ ionizes in aqueous solutions to form Ag⁺ and  NO^3- ions. 

On electrolysis, either Ag⁺ ions or H₂O molecules can be reduced at the cathode. But the reduction potential of Ag⁺ ions is higher than that of H₂O. 

Hence, Ag⁺ ions are reduced at the cathode. Similarly, Ag metal or H₂O molecules can be oxidized at the anode. But the oxidation potential of Ag is higher than that of H₂O molecules. 

Therefore, Ag metal gets oxidized at the anode. 

(ii) Pt cannot be oxidized easily. Hence, at the anode, oxidation of water occurs to liberate O₂. At the cathode, Ag⁺ ions are reduced and get deposited. 

(iii) H₂SO₄ ionizes in aqueous solutions to give H⁺ and  SO₄^2-   ions. 

On electrolysis, either of H⁺ ions or H₂O molecules can get reduced at the cathode. But the reduction potential of H⁺ ions is higher than that of H₂O molecules. 

Hence, at the cathode, H⁺ ions are reduced to liberate H₂ gas.