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Electrochemistry

Question
CBSEENCH12010714

The reduction potential of hydrogen half-cell will be negative if 

  • p(H2) = 1 atm and [H+] = 2.0 M

  • p(H2) = 1 atm and [H+] = 1.0 M

  • p(H2) = 2 atm and [H+] = 1.0 M

  • p(H2) = 2 atm and [H+] = 2.0 M

Solution

C.

p(H2) = 2 atm and [H+] = 1.0 M

2 straight H to the power of plus left parenthesis aq right parenthesis space plus space 2 straight e to the power of minus space rightwards arrow with space on top space straight H subscript 2 space left parenthesis straight g right parenthesis
straight E subscript red space equals space straight E subscript red superscript 0 minus fraction numerator 0.0591 over denominator straight n end fraction space log space fraction numerator straight P subscript straight H subscript 2 end subscript over denominator left parenthesis straight H to the power of plus right parenthesis squared end fraction
straight E subscript red space equals space 0 space minus fraction numerator 0.0591 over denominator 2 end fraction space log space fraction numerator 2 over denominator left parenthesis 1 right parenthesis squared end fraction
straight E subscript red space equals space minus fraction numerator 0.0591 over denominator 2 end fraction space log space 2
Thus correct answer is c.