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JEE Main Chemistry Ionic Equilibrium 2026 JEE Main 2026 (28 January Shift 1)

JEE Main Chemistry Question (2026) — Solution

Question

Consider a weak base ' B ' of pK _ b =5.699. ' x ' mL of 0.02 M HCl and ' y ' mL of 0.02 M weak base ' B ' are mixed to make 100 mL of a buffer of pH 9 at 25^ C . The values of ' x ' and ' y ' respectively are: [Given: 2=0.3010, 3=0.4771, 5=0.699]

Options

  1. A. \( array |c|c| x & y \\ 85.7 & 14.3 \\ array \)
  2. B. \( array |c|c| x & y \\ 14.3 & 85.7 \\ array \)
  3. C. \( array |c|c| x & y \\ 11.1 & 88.9 \\ array \)
  4. D. \( array |c|c| x & y \\ 42.7 & 57.3 \\ array \)

Answer

B. \( array |c|c| x & y \\ 14.3 & 85.7 \\ array \)

Step-by-step solution

pOH = pK_b + [ Salt Base ] 5 = 5.699 + [ Salt Base ] x y - x = 1 5 6x = y 7x = 100 x = 100 7 ml y = 600 7 ml

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