\(Cr_2O_7^{2-} + 14H^+ + 6e^- \longrightarrow 2Cr^{3+} + 7H_2O\) The quantity of charge, in coulombs, needed to reduce 1 mole of \(Cr_2O_7^{2-}\) is (Given \(\text{1 F = 96500 C mol}^{–1})\) |
\(57.9 × 10^5\, \ C\) \(5.79 × 10^5\, \ C\) \(1.9 × 10^5\, \ C\) \(19.3 × 10^5\, \ C\) |
\(5.79 × 10^5\, \ C\) |
The correct answer is option 2. \(5.79 × 10^5\, \ C\). The balanced half-reaction provided is: \[ Cr_2O_7^{2-} + 14H^+ + 6e^- \longrightarrow 2Cr^{3+} + 7H_2O \] This reaction involves the reduction of \(Cr_2O_7^{2-}\) to \(2Cr^{3+}\) by gaining electrons. The quantity of charge (in coulombs) needed to reduce 1 mole of \(Cr_2O_7^{2-}\) can be calculated by multiplying the number of moles by the Faraday constant (\(F\)). From the balanced half-reaction, 6 moles of electrons are involved in the reduction of 1 mole of \(Cr_2O_7^{2-}\). So, the quantity of charge (\(Q\)) is given by: \( Q = n \times F \) \( Q = 579000 \, \text{C} \) Therefore, the correct option is: (2) \(5.79 \times 10^5\, \text{C}\) |