A. Lechlanche cell the electrode reaction occurs at Lechlanche cell are
At anode `Zn(s)rarrZn^(2)+2e^(-)` ltbr. At cathode `MnO_(2)+NH_(4)^(+)+e^(-)rarrMnO(OH)+NH_(3)`
B. Ni-Cd cell is rechargeable so. It has more life time.
C. Fuel cell produces energy due to combustion So, fuel cell converts energy of combustion into electrical energy e.g. `2H_(2)+O_(2)rarr2H_(2)O`
D. Mercury cell does not involve any ion in solution and is used in heating aids.
