Electrolysis

anode polarity in electrolytic cells

The anode in electrolytic cells is positively charged, attracting anions and facilitating oxidation reactions during electrolysis.

anode polarity in galvanic cells

The anode in electrochemical cells are negatively charged

cathode polarity in galvanic cells

The cathode in galvanic cells is positively charged, attracting cations and facilitating reduction reactions.

cathode polarity in electrolytic cells

The cathode in electrolytic cells is negatively charged, attracting cations and facilitating reduction reactions during electrolysis.

molten cathode

metal ions are reduced at the cathode

molten anode

non-metal ions are oxidised at the cathode

aqueous anode: inert, iodine is present

I2 is formed. i.e. 2I^- (aq) TO I2(aq) + 2E^-

aqueous anode: inert, high concentration of cl or br

Cl2 or Br2 are formed i.e. 2Cl^- (aq) TO Cl2(g) + 2E^- or 2Br^- (aq) TO Br2(g) + 2E^-

aqueous anode: inert, low concentration of cl or br

oxygen evolved at the anode i.e. 4OH^- (aq) TO O2(g) + 2H2O(l) + 4E^-

aqueous anode: non-inert

metal anode is oxidised, becomes lighter

aqueous cathode: Na+, K+, Li+, Mg2+, Ca2+, Al3+, Ba2+

hydrogen is evolved. 2H2O(L) + 2e^- TO H2(g) + 2OH^- (aq)

aqueous cathode: H+ from an acid

H2 is gas is formed at the cathode. 2H+ (aq) + 2e^- TO H2(g)

aqueous cathode: other

ions are reduced at the cathode. i.e Pb2+ (aq) + 2e^- TO Pb(s)