20. Electrochemistry

If the overall redox reaction for an electrolytic cell is given below, what will happen to the mass of the cobalt electrode?

Co²⁺ (aq) + Cu (s) ⇌ Co (s) + Cu²⁺(aq)

Magnesium, the element, is produced commercially by electrolysis from a molten salt (the 'electrolyte') using a cell similar to the one shown here. (c) Recall that in an electrolytic cell the anode is given the + sign and the cathode is given the – sign, which is the opposite of what we see in batteries. What half-reaction occurs at the anode in this electrolytic cell?

Porous pellets of TiO₂ can be reduced to titanium metal at the cathode of an electrochemical cell containing molten CaCl₂ as the electrolyte. When the TiO₂ is reduced, the O^2-ions dis-solve in the CaCl₂ and are subsequently oxidized to O₂ gas at the anode. This approach may be the basis for a less expensive process than the one currently used for producing titanium.

(c) Write balanced equations for the anode, cathode, and overall cell reactions.

Porous pellets of TiO₂ can be reduced to titanium metal at the cathode of an electrochemical cell containing molten CaCl₂ as the electrolyte. When the TiO₂ is reduced, the O^2-ions dis-solve in the CaCl₂ and are subsequently oxidized to O₂ gas at the anode. This approach may be the basis for a less expensive process than the one currently used for producing titanium.

(a) Label the anode and cathode, and indicate the signs of the electrodes.