To find the degree of dissociation of the acetic acid, we first need to calculate the molar conductivity
(Λm) of the solution. The formula for molar conductivity is:
Λm=where:
κ (kappa) is the specific conductance.
c is the concentration of the acetic acid solution.
Given:
κ=1.65×10−4Scm−1c=0.02MSubstituting these values into the formula for molar conductivity:
Λm= Calculating this gives:
Λm=8.25×10−3Scm2mol−1Next, we need to find the limiting molar conductivity
(Λm0) of acetic acid, which is the sum of the limiting molar conductivities of its ions:
Λm0=λO+∘+λCH3COO0Given:
λO++∘=349.1Scm2mol−1λCH3COO−∘=40.9Scm2mol−1 Calculating the limiting molar conductivity:
Λm0=349.1+40.9=390Scm2mol−1 The degree of dissociation
(α) can now be determined using the ratio of the molar conductivity to the limiting molar conductivity:
α=Substituting the values we calculated:
α=Calculating this gives:
α=2.115×10−5≈0.021The degree of dissociation of the acetic acid is approximately 0.021 . Hence, the correct option is:
Option A