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JEE Main 20208 JanuaryMorning Shift
Exam
JEE Main
Year
2020
Date
8 January
Shift
Morning Shift
Subject
Chemistry
Chapter
Electrochemistry

JEE Main 2020 · 8 January · Morning Shift · Chemistry · Electrochemistry

What would be the electrode potential for the given half-cell...

What would be the electrode potential for the given half-cell reaction at pH = 5 ? _ _ _ _ _ _ _ _ _ .<br />2{H}_{2}O \to {O}_{2} + 4\overset{⊕}{\text{H}}+ 4{e}^{-}; {E}_{red}^{0} = 1.23V
\left(R = 8.314J{mol}^{- 1}{K}^{- 1}; Temp = 298K; oxygenunderstandard . atm . pressureof1bar\right)

Correct answer

0.93

Step-by-step solution

On applyinf Nernst equation-

E=E°−0.0591nlogQE=−1.23−0.05914log[H+]4E = E ° - \dfrac{0 . 0591}{n}logQE = - 1 .23 - \dfrac{0 .0591}{4}log{[ {H}^{+} ]}^{4}
=1.23+0.0591×pH=−1.23+0.0591×5= 1.23 + 0.0591 \times pH = - 1.23 + 0.0591 \times 5
=−1.23+0.2955=−0.9345V=−0.93V= - 1.23 + 0.2955 = - 0.9345V = - 0.93V

The Nernst equation defines the relationship between cell potential to standard potential and to the activities of the electrically active (electroactive) species. It relates the effective concentrations (activities) of the components of a cell reaction to the standard cell potential.

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