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Write the overall reaction that occurs during use (discharging) of nickel- cadmium cell. Is it a primary or a secondary cell? Mention its one merit over the lead storage cell. |
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Answer» Solution :(i) Nickel-cadmium storage cell: It is another rechargeable cell. It consists of cadmium anode and the CATHODE is made of a metal grid containing nickel (IV) oxide. These are immersed in KOH solution. The overall reactions occuring: Anode: `Cd(s)+2OH^(-) (aq) to Cd(OH)_2(s)+2e^(-)` Cathode: `NiO_2(s)+2H_2O(l)+2e^(-)to NI(OH)_2(s)+2OH^(-) (aq)` Net reaction `Cd(s)+NiO_2(s)+2H_2O(l)to Cd(OH)_2(s)+Ni(OH)_2(s)` discharging Ni-Cd cell is : `Cd(s)+2NI(OH)_3(s)to CdO(s)+2Ni(OH)_2(s)+H_2O(l)` (ii) Primary/Secondary: It is a secondary cell. (iii) Merit over lead storage cell: As is evident, there are no gaseous products, the products formed. adhere to the electrodes and can be reconverted by recharging process. |
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