Write down the half-reaction that takes place at the cathode

Answer 1

The half-reaction that takes place at the cathode depends on the specific electrochemical cell or system being considered. In general, however, common half-reactions at the cathode can involve the reduction of anionic species or the gain of electrons. Some possible examples include:

1. Reduction of hydrogen ions (H+) to hydrogen gas (H2):
2H+ + 2e- -> H2

2. Reduction of oxygen molecules (O2) to hydroxide ions (OH-):
O2 + 2H2O + 4e- -> 4OH-

3. Reduction of metal cations (M+) to metal atoms (M):
M+ + e- -> M

Remember that the direction of the electron flow and the specific half-reaction depend on the context of the electrochemical cell or system being considered.