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KCET2014ChemistryThermodynamics (C)

For hydrogen - oxygen fuel cell at one atm and ( 298 ~K ) ( H ₂(g)+ 1 2 O _ 2(g) H ₂ O (l) ; G ^ =-240 ~kJ ) ( E ^ ) for the cell is approximately, (Given ( F =96,500 C ) )

Options

  1. A( 1.24 ~V )
  2. B( 1.26 ~V )
  3. C( 2.48 ~V )
  4. D( 2.5 ~V )

Correct answer

A. ( 1.24 ~V )

Step-by-step solution

At Anode : 2 H ₂(g)+4 OH ⁻(a q) 4 H ₂ O (l)+4 e⁻ At Cathode : O ₂(g)+2 H ₂ O (l)+4 e⁻ 4 OH ⁻(a q) Overall : 2 H ₂(g)+ O ₂(g) 2 H ₂ O (1) ; G^ -240 2=-480 ~kJ =-480000 ~J Now, G^ =-n F E_ cell ^ -480 ~kJ =-4 96500 E_ cell E_ cell ^ = -480000 -4 96500 =1.24 ~V

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