Chemistry 9701 · AS & A Level · Electrochemistry

Electrochemistry — practice question

An electrochemical cell is made from two half-cells: an $\text{Sn}^{4+}/\text{Sn}^{2+}$ half-cell and an $\text{Al}^{3+}/\text{Al}$ half-cell.
(a)[1]

State the electrode material used in each half-cell. • $\text{Sn}^{4+}/\text{Sn}^{2+}$ half-cell • $\text{Al}^{3+}/\text{Al}$ half-cell

(b(i))[2]

Use the Nernst equation to work out the electrode potential, $E$, of the $\text{Sn}^{4+}/\text{Sn}^{2+}$ half-cell under these conditions.

(b(ii))[1]

Calculate the $E_{\text{cell}}$ under these conditions.

(b(iii))[2]

Write an equation for the overall cell reaction that takes place.

(c)[4]

Aluminium is made industrially by electrolysis of a melt that contains large amounts of $\text{Al}^{3+}$ ions. Calculate the mass of aluminium obtained when a current of $300\,000\,\text{A}$ flows for $24$ hours. Give your answer to three significant figures.

(d)[2]

Explain why chromium metal cannot be obtained by electrolysis of dilute aqueous chromium(II) sulfate. Your response should include data from the Data Booklet.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: Pt / platinum

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