Chemistry 9701 · AS & A Level · Electrochemistry

Electrochemistry — practice question

X is an element with metallic properties.
(a(i))[4]

Produce a fully labelled diagram showing how the standard electrode potential, $E^\circ$, for $\text{X}^{2+}(\text{aq})/\text{X}(\text{s})$ may be determined.

(a(ii))[1]

Which conditions must be satisfied for the measured value to count as a standard electrode potential?

(a(iii))[1]

State which charge carriers pass current through the solutions and through the wire.

(b(i))[1]

An electrochemical cell was assembled from an $\text{X}^{2+}(\text{aq})/\text{X}(\text{s})$ half-cell ($E^\circ = -0.40\,\text{V}$) and an $\text{Ag}^+(\text{aq})/\text{Ag}(\text{s})$ half-cell ($E^\circ = +0.80\,\text{V}$). Write an equation for the reaction that would occur when the electrodes of this cell are connected by a wire.

(b(ii))[4]

While current flowed for a time, the Ag electrode increased in mass by $1.30\,\text{g}$ and the electrode made of metal X decreased in mass by $0.67\,\text{g}$. Calculate the $A_r$ of metal X, hence suggest an identity for X. Show all your working. The Data Booklet may be used in this question.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Salt bridge and voltmeter included

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