Electrochemistry
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See all →- For the Daniell cell \(\mathrm{Zn|Zn^{2+}(1M)||Cu^{2+}(1M)|Cu}\), \(E^\circ_{\mathrm{Zn}}=-0.76\) V and \(E^\circ_{\mathrm{Cu}}=+0.34\) V. The standard Gibbs energy change is Answer: C. -212.3 kJ E^°_cell=0.34-(-0.76)=1.10 V; Δ G^°=-nFE^°=-2×96500×1.10=-212.3 kJ. 1
- A current of 2 A is passed through CuSO4 solution for 965 s. The mass of copper deposited is (Cu = 63.5, F = 96500 C) Answer: A. 0.635 g Q=1930 C =0.02 F; Cu²⁺ needs 2F/mol, so 0.01 mol =0.635 g. 1
- The electrode potential of a hydrogen electrode (\(P_{H_2}\) = 1 bar) dipped in a solution of pH 3 at 298 K is Answer: D. -0.177 V E=-0.0592 pH=-0.0592×3≈-0.177 V. 1
- The conductivity of a 0.1 M solution of an electrolyte is 0.0129 S cm-1. Its molar conductivity is Answer: A. 129 S cm2 mol-1 Lambda_m=1000kappa/C=1000×0.0129/0.1=129 S cm² mol⁻¹. 1