JEE Advanced 2017 · Paper 2 · Chemistry Q2

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ChemistrySingle correct+3 / -1Question 20 of 54

For the following cell,

$\mathrm{Zn(s)\,|\,ZnSO_4(aq)\,\|\,CuSO_4(aq)\,|\,Cu(s)}$

when the concentration of $\mathrm{Zn^{2+}}$ is 10 times the concentration of $\mathrm{Cu^{2+}}$ , the expression for $\Delta G$ (in $\mathrm{J\,mol^{-1}}$ ) is

[F is Faraday constant; R is gas constant; T is temperature; $E^o(cell) = 1.1$ V]

1.1F

2.303RT − 2.2F

2.303RT + 1.1F

−2.2F

Answer and worked solution

Official answer: B

Cell reaction. $\ce{Zn + Cu^{2+} -> Zn^{2+} + Cu}$ , with $n=2$ .

emf.
$E=1.1-\frac{2.303RT}{2F}\log10=1.1-\frac{2.303RT}{2F}.$

Gibbs energy.
$\Delta G=-2FE=2.303RT-2.2F.$

(B)

Topics:Nernst equation Gibbs energy and EMF

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JEE Advanced 2017 · Paper 2, Chemistry question 2