Question

12. Which of the following statements is true about a nickel-cadmium dry cell? (Points : 3) The cathode reaction is Cd + 2OH Cd(OH)2 + 2e. The cathode reaction is Cd + NiO2 + 2H2O Cd(OH)2 + Ni(OH)2. The cathode reaction is NiO2+ H2O + 2e Ni(OH)2 + 2OH. The anode reaction is NiO2 + H2O + 2e Ni(OH)2 + 2OH.

Answer 1

The correct answer among the options given is the first one. The cathode reaction for a nickel-cadmium dry cell is Cd + 2OH Cd(OH)2 + 2e. It should be remembered that at the cathode reduction always happen and reduction is the gain of electrons. As we can see from the half reaction, there is a gain of 2 electrons.