Explain why iron is obtained from its ores using chemical reducing agents but aluminium is obtained from its ores using electrolysis.

Both carbon monoxide and hydrogen can be used to reduce iron ores. State the equations for the reduction of magnetite, Fe₃O₄, with

(i)     carbon monoxide.

(ii)     hydrogen.

Explain why much of the iron produced in a blast furnace is converted into steel.

State the materials used for the positive and negative electrodes in the production of aluminium by electrolysis.

Positive electrode:

Negative electrode:

Al is more reactive than Fe / Al is higher than Fe in the reactivity series;

it is harder to reduce aluminium ores compared to iron ores / \({\text{F}}{{\text{e}}^{3 + }}\) is a better oxidizing agent than \({\text{A}}{{\text{l}}^{3 + }}\) / OWTTE;

(i)     \({\text{F}}{{\text{e}}_{\text{3}}}{{\text{O}}_{\text{4}}} + {\text{4CO}} \to {\text{3Fe}} + {\text{4C}}{{\text{O}}_{\text{2}}}\);

(ii)     \({\text{F}}{{\text{e}}_3}{{\text{O}}_4} + {\text{4}}{{\text{H}}_2} \to {\text{3Fe}} + {\text{4}}{{\text{H}}_2}{\text{O}}\);

steel has more desirable (physical) characteristics than iron / steel is stronger than iron / OWTTE;

by adjusting the composition of steel it can be given specific properties / OWTTE;

Positive electrode

graphite/carbon;

Negative electrode

graphite/carbon (on a steel liner);

Part (a), which required candidates to explain the relative reactivity of iron and aluminium, proved challenging for most candidates.

Many candidates could correctly state the products of reduction of magnetite but several failed to balance the equations and thus lost marks.

Most candidates could explain the advantages of steel over iron in part (c).

Very few candidates could identify the electrodes used in the production of aluminium, but most could explain the importance of recycling aluminium in part (d).