The equivalent conductance of M/32 solution of a weak monobasic acid is 8.0 mhos cm^2 and at infinite dilution is 400 mhos cm^2. The dissociation constant of the acid is

1- 1.25 x 10^-4 2- 1.25 x 10^-5

3- 1.25 x 10^-6 4- 6.25 x 10^-4

The degree of dissociation is related to equivalent conductance and equivalent conductance at infinite dilution :
The degree of dissociation α = Λ(equivalent conductance at given dilution)/​Λ(equivalent conductance at given dilution)                                      
= 8 mho cm2/400 mho cm2
Dissociation constant of an acid Ka = C α​2
                                                         = 1/32 M x (8 mho cm2/400 mho  cm2)2
                                                        = 1.25 x 10-5
Correct answer is 2.
   

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