The molar conductivity of 0 . 007 M acetic acid is 20 S cm 2 mol - 1 . What is the dissociation constant of…

The molar conductivity of 0.007 M acetic acid is 20 S cm2 mol-1. What is the dissociation constant of acetic acid? Choose the correct option.

λH+∘=350 S cm2 mol-1λCH3COO-∘=50 S cm2 mol-1

  1. 1.75×10-4 mol L-1
  2. 2.50×10-4 mol L-1
  3. 1.75×10-5 mol L-1
  4. 2.50×10-5 mol L-1

Solution

λCH3COOH∘=λCH3COO-∘+λH+∘

λCH3COO-∘=350+50=400 S cm2 mol-1

λCH3COOH=20Scm2 mol-1 given

α=λCH3COOHλCH3COOH∘=20400=5×10-2

Ka=cα2=0.007×5×10-22=1.75×10-5 molL-1

Asked in: NEET 2021

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