Answer:
Follows are the solution to the given question:
Explanation:
Following are the balanced redox equation:
[tex]Cr_2O_7^{2-} + 6 Fe^{2+} + 14H^{+} \to 2Cr^{3+} + 6 Fe^{3+} + 7H_2O[/tex]
Calculating the average volume of the dichromate:
[tex](i)\ 13.8 - 2.3 = 11.5 \ ml\\\\(ii)\ 24.4 - 13.8 = 10.6\ ml\\\\(ii)\ 35.2 - 24.4 = 10.8 \ ml\\\\(iv)\ 45.9 - 35.2 = 10.7\ ml[/tex]
[tex]Mean\ volume = 10.9\ ml = 0.0109\ L\\\\moles\ Fe^{2+} \ titrated = 0.01500 \ L \times 0.07\ \frac{mol}{L} = 0.00105 \\\\moles\ Cr_2O_7^{2-}\ required = 0.00105\ mol\ Fe^{2+} \times 1 \ mol\ \frac{Cr_2O_7^{2-}}{6 \mol\ Fe^{2+} } = 0.000175 \ moles\ Cr_2O_7^{2-}\\\\Concentration \ of\ Cr_2O_7^{2-} = \frac{0.000175\ moles}{0.0109\ L} = 0.01606\ M\\\\[/tex]