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NTA Abhyas JEE Main2020ChemistryIonic EquilibriumPractice

Calculate the number of moles of N H 4 C l that should be added to one litre of 1.0 M N H 4 O H to prepare buffer solution with pH = 9 K b =2 × 10 − 5 , take log 2 = 0 .3

Options

  1. A3.4
  2. B2.6
  3. C1.5
  4. D2

Correct answer

D. 2

Step-by-step solution

It is basic buffer pOH = pK b + log [salt] [weak base] pOH = 14 − 9 = 5 5 = 4 .7 + log x 1 0 .3 = log ​ x ⇒ x = 2

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