59 Write the reactions at cathode and anode during electrolytic reduction of aluminium oxide.

Q. (i) Name the solution used to react with Bauxite as a first step in obtaining pure aluminium oxide, in the Baeyer's process.
(ii) Write the equation for the reaction where the aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide.
(iii) Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.
(iv) Write the equation for the reaction that occurs at the cathode during the extraction of aluminium by electrolysis.
(v) Explain why it is preferable to use a number of graphite electrodes as anode instead of a single electrode, during the above electrolysis.

Q. Draw labelled diagram of Hall-Heroult Electrolytic cell for the extraction of aluminium. Write anode and cathode reactions.

Q. Assertion :Anode is the electrode at which oxidation occurs and cathode is the electrode at which reduction occurs. Reason: Anode and cathode in electrochemical cells and electrolytic cells have opposite polarity.

Q. Assertion: Starting from aq. copper [II] sulphate solution, equations for the reactions at the cathode and anode during electrolysis of aq. $CuS{O}_4$ using active copper electrodes is;
at anode:
$C{u}^{+2}+2e^{-}\to Cu$
at cathode:
$Cu\to C{u}^{+2}+2e^{-}$
Reason: Oxidation always take place at anode and reduction at cathode.

Q. Identify the reaction during electrolytic reduction of alumina at cathode.