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Electrochemistry question

2024 · 1 Feb · Shift 2 · Q26
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Electrochemistry question

2024 · 1 Feb · Shift 2 · Q26

JEE MainChemistryElectrochemistryNumerical+4 / −1
The amount of electricity in Coulomb required for the oxidation of 1 mol1 \mathrm{~mol}1 mol of H2O\mathrm{H}_2 \mathrm{O}H2​O to O2\mathrm{O}_2O2​ is ‾\underline{\hspace{2cm}}​×105C\times 10^5 \mathrm{C}×105C.
Numerical answer
View written solutionFree

Correct answer: 2

  1. Write the oxidation half-reaction of water

    In acidic medium, oxidation of water to oxygen is: 2H2O→O2+4H++4e−2H_2O \rightarrow O_2 + 4H^+ + 4e^-2H2​O→O2​+4H++4e−

  2. Relate moles of water to moles of electrons

    From the reaction, 2 mol H2O→4 mol e−2\text{ mol } H_2O \rightarrow 4\text{ mol } e^-2 mol H2​O→4 mol e−

    Therefore, 1 mol H2O→2 mol e−1\text{ mol } H_2O \rightarrow 2\text{ mol } e^-1 mol H2​O→2 mol e−

  3. Use Faraday's constant

    Charge required for 1 mole of electrons is: 1F=96500 C1F = 96500\,C1F=96500C

    So for 222 moles of electrons: Q=2F=2×96500=193000 CQ = 2F = 2 \times 96500 = 193000\,CQ=2F=2×96500=193000C

  4. Express in the required form

    193000 C=1.93×105 C193000\,C = 1.93 \times 10^5\,C193000C=1.93×105C

    Since the blank is in the form ‾×105 C\underline{\hspace{2cm}} \times 10^5\,C​×105C, the value is approximately: 2×105 C2 \times 10^5\,C2×105C

  5. Compare with stored answer

    Derived answer = 222

    Stored correct answer = 222

    Hence, they agree.

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