Standard electrode potential for \( \text{Sn}^{4+}/\text{Sn}^{2+} \) couple is +0.15 V and that for the \( \text{Cr}^{3+}/\text{Cr} \) couple is -0.74 V. The two couples in their standard states are connected to make a cell. The cell potential will be:
To calculate the cell potential (\( E^\circ_{\text{cell}} \)), we use the standard electrode potentials of the given redox couples.
Given data:
\( E^\circ_{\text{Sn}^{4+}/\text{Sn}^{2+}} = +0.15V \)
\( E^\circ_{\text{Cr}^{3+}/\text{Cr}} = -0.74V \)
Step 1: Understanding the cell potential. The cell potential is calculated by subtracting the anode potential from the cathode potential. The two given standard electrode potentials are for the Sn^{4+}/Sn^{2+} couple (+0.15 V) and the Cr^{3+}/Cr couple (-0.74 V).
Step 2: Calculation. The cell potential is given by: \[ E_{\text{cell}} = E_{\text{cathode}} - E_{\text{anode}} = (+0.15 \, \text{V}) - (-0.74 \, \text{V}) = +0.89 \, \text{V} \]
Step 3: Conclusion. Thus, the cell potential is +0.89 V, corresponding to option (B). \vspace{10pt}


Electricity is passed through an acidic solution of Cu$^{2+}$ till all the Cu$^{2+}$ was exhausted, leading to the deposition of 300 mg of Cu metal. However, a current of 600 mA was continued to pass through the same solution for another 28 minutes by keeping the total volume of the solution fixed at 200 mL. The total volume of oxygen evolved at STP during the entire process is ___ mL. (Nearest integer)
Given:
$\mathrm{Cu^{2+} + 2e^- \rightarrow Cu(s)}$
$\mathrm{O_2 + 4H^+ + 4e^- \rightarrow 2H_2O}$
Faraday constant = 96500 C mol$^{-1}$
Molar volume at STP = 22.4 L

