JEE Main & Advanced Chemistry Redox Reactions / रेडॉक्स अभिक्रियाएँ Question Bank Mock Test - Redox Reactions

  • question_answer
    If 10 g of \[{{V}_{2}}{{O}_{5}}\], is dissolved in acid and is reduced to \[{{V}^{2+}}\] by zinc metal, how many mole of I, could be reduced by the resulting solution if it is further oxidised to \[V{{O}^{2+}}\]ions? [Assume no change in state of \[Z{{n}^{2+}}\]ions] (V=51,O=16, I=127):

    A) 0.11 mole of \[{{I}_{2}}\]

    B) 0.22 mole of \[{{I}_{2}}\]

    C) 0.055 mole of \[{{I}_{2}}\]

    D) 0.44 mole of \[{{I}_{2}}\]

    Correct Answer: A

    Solution :

    [a] \[\underset{+5}{\mathop{{{V}_{2}}{{O}_{5}}}}\,+6{{e}^{-}}\to \underset{+2}{\mathop{2{{V}^{2+}}}}\,\] Molecular mass of \[{{V}_{2}}{{O}_{5}}=51\times 2+5\times 16=182\] 1 mol of \[{{V}_{2}}{{O}_{5}}\]produces 2 moles of \[{{V}^{2+}}\] \[\therefore \frac{10}{182}\]moles of \[{{V}_{2}}{{O}_{5}}\]produce \[2\times \frac{10}{182}=0.11\]moles of \[{{V}^{2+}}\] \[\underset{+2}{\mathop{{{V}^{2+}}}}\,\to V{{\underset{0}{\mathop{O}}\,}^{2+}}+2{{e}^{-}}\]               (1) \[\underset{0}{\mathop{{{I}_{2}}}}\,+2{{e}^{-}}\to \underset{-1}{\mathop{2{{I}^{-}}}}\,\]                            (2) On adding (1) and (2) \[{{V}^{2+}}+{{I}_{2}}\to 2{{I}^{-}}+V{{O}^{2+}}\] 1 mole of \[{{V}^{2+}}\]reduces 1 mole of \[{{I}_{2}}\] \[\therefore 0.11\]moles of \[{{V}^{2+}}\]reduce 0.11 moles of \[{{I}_{2}}\]


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