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The degree of dissociation of a weak monoprotic acid of concentration 1.2   ×   10 – 3   M having K a = 1.0 × 10 – 4 is

Options

  1. A1
  2. B10
  3. C15
  4. D25

Correct answer

D. 25

Step-by-step solution

By α = K a C = 1 0 - 4 1.2 × 1 0 - 3 = 1 12 % α = 28.86 % , as value of α is greater than 5% so we can not take assumptions and will have to use the exact formula. So α will be given by: α = - 1 0 - 4 + 1 0 - 8 + 4 × 1 0 - 3 × 1.2 × 1 0 - 4 2 × 1.2 × 1 0 - 3 So the correct value of α = 25 %

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