A cell contains two hydrogen electrodes. The negative electrode is in contact with a solution of 1 0 - 6 M hydrogen ion. The EMF of the cell is 0.118 V at 298 K. The concentration of H + ion at the positive electrode is 1 0 - x ,The value of 'x' is

Question

A cell contains two hydrogen electrodes. The negative electrode is in contact with a solution of 1 0 - 6 M hydrogen ion. The EMF of the cell is 0.118 V at 298 K. The concentration of H + ion at the positive electrode is 1 0 - x ,The value of 'x' is,

MARKS App · Accepted Answer

Cell reaction would be like, assume the concentration of hydrogen ion in positive electrode is 'x' P t H 2 1 a t m H + 1 0 - 6 M H + x M P t H 2 1 a t m , i f E c e l l = 0.118 V . At cathode: 2 H + x M + 2 e - → H 2 ( g ) At anode: H 2 g → 2 H + 1 0 - 6 M + 2 e - E C e l l = E C e l l ο - 0.591 2 log ⁡ H + a n o d e 2 H + c a t h o d e 2 E C e l l = E C e l l ο - 0.591 2 log ⁡ H + a n o d e H + c a t h o d e 2 E C e l l = E C e l l ο - 0.0591 2 log ⁡ 1 0 - 6 x 2 0.118 = 0 - 0.0591 2 log ⁡ 1 0 - 6 x 2 0.118 × 2 = - 0.0591 log ⁡ 1 0 - 6 x 2 0.118 × 2 0.0591 = - log ⁡ 1 0 - 6 x 2 - log ⁡ 1 0 - 6 x 2 = 0.118 × 2 0.0591 - 2 log ⁡ 1 0 - 6 x = 4 log ⁡ 1 0 - 6 x = - 2 1 0 - 6 x = 1 0 - 2 x = 1 0 - 4

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