Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main202226 Jul 2022Evening ShiftChemistryIonic EquilibriumActual

Class XII students were asked to prepare one litre of buffer solution of pH 8 . 26 by their chemistry teacher. The amount of ammonium chloride to be dissolved by the student in 0 . 2 M ammonia solution to make one litre of the buffer is (Given pK b NH 3 = 4 . 74 ; Molar mass of NH 3 = 17 g mol - 1 . Molar mass of NH 4 Cl = 53 . 5 g mol - 1 )

Options

  1. A53 . 5   g
  2. B72 . 3   g
  3. C107   g
  4. D126 g

Correct answer

C. 107   g

Step-by-step solution

A mixture of NH 3 and NH 4 Cl will form a basic buffer. pH of final solution = 8 . 26 pOH of final solution = 14 - 8 . 26 = 5 . 74 Let the number of moles of NH 4 Cl added to 1   L solution of be x . Using Henderson’s equation. pOH = pK b + log NH 4 Cl NH 3 5 . 74 = 4 . 74 + log x 0 . 2 ∴   x = 2 The amount of ammonium chloride to be dissolved by the student in 0 . 2 M ammonia solution to make one litre of buffer = 2 × 53 . 5 = 107 g

Practice Ionic Equilibrium on Quantrex Academy →

More from Ionic Equilibrium

Given is a concentrated solution of a weak electrolyte A_xB_y of concentration 'c' and dissociation constant 'K'. The degree of dissociation is given by : 2026M₃ A₂ is a sparingly soluble salt of molar mass y g mol ⁻¹ and solubility x g L ⁻¹ . The ratio of the molar concentration of the anion ( A³⁻ ) to the solubility product of the salt 2026Arrange the following resultant mixtures in increasing order of their pH values A. 10 mL 0.2 M Ca(OH)₂ + 25 mL 0.1 M HCl B. 10 mL 0.01 M H₂ SO₄ + 10 mL 0.01 M Ca(OH)₂ C. 10 mL 0.1 202620 mL of a solution of acetic acid required 28.4 mL of 0.1 M NaOH for its neutralization. A solution (X) was prepared by mixing 20 mL of the above acetic acid and 14.2 mL of 0.1 M 2026The pH of a solution obtained by mixing 5 mL of 0.1 M NH₄OH solution with 250 mL of 0.1 M NH₄Cl solution is _____ 10⁻² . (Nearest integer) Given: pK_b(NH₄OH) = 4.74 2 = 0.30 3 = 0. 2026The first and second ionization constants of a weak dibasic acid H₂ A are 8.1 10⁻⁸ and 1.0 10⁻¹³ respectively. 0.1 mol of H₂ A was dissolved in 1 L of 0.1 M HCl solution. The conce 2026At 25°C , 20.0 mL of 0.2 M weak monoprotic acid HX is titrated against 0.2 M NaOH. The pH of the solution (a) at the start of the titration (when NaOH has not been added) and (b) w 2026The solubility product constants of Ag₂CrO₄ and AgBr are 32x and 4y respectively at 298 K. The value of ( molarity of Ag₂CrO₄ molarity of AgBr ) can be expressed as : 2026 Full Ionic Equilibrium list All JEE Main PYQs