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ChemistryCBSE Class 12 · Board exam 2024, set 56/1/1 · 3 marks · Short answer

CBSE Class 12 Chemistry 2024: question 22

Set in the CBSE Class 12 board exam of 2024, paper 56/1/1, section C, question 22, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q22 · 3 marks · Short answerElectrochemistry

When a certain conductivity cell was filled with 0·05 M KCl solution, it has a resistance of 100 ohm at 25ºC. When the same cell was filled with 0·02 M solution, the resistance was 90 ohm. Calculate the conductivity and molar conductivity of solution.
(Given : Conductivity of 0·05 M KCl solution = )

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 56/1/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

The cell constant is the same for both solutions — find it using KCl.

Hint 2

Then use κ = G*/R and Λm = κ×1000/C.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. Cell constant from KCl:

    1 mark
  2. Conductivity of AgNO₃:

    1 mark
  3. Molar conductivity:

    1 mark

Answer: κ = 0.015 S cm⁻¹; Λm = 750 S cm² mol⁻¹

Where the marks are

  • Cell constant = 1.35 cm⁻¹ (1 mark)
  • Conductivity of AgNO₃ = 0.015 S cm⁻¹ (1 mark)
  • Molar conductivity = 750 S cm² mol⁻¹ with unit (1 mark; ½ deducted for missing/wrong unit)

Revise the chapter

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.