HC2H3O2, HNO3 and NH4C2H3O2 -all dissociate in aqueous solution to produce two ions, one positively charged and one negatively charged. Ca(NO3)2, on similar dissociation produces 3 ions, one dipositive and two negative. Therefore, the solution having lowest electrical conductivity will be from options A), B), and C).
A) HC2H3O2 is a weak acid, having very low dissociation constant value. Thus in 0.1 M solution, the ionic concentration will be pretty low, indicating a very low value of conductivity.
B) HNO3 is a strong electrolyte dissociating completely in aqueous solution, in all concentrations. So, its 0.1 M solution will record a very high value of conductivity.
C) NH4C2H3O2is the salt of a weak acid (HC2H3O2), and a weak base (NH4OH). Being a salt, its dissociation constant will be larger than the weak acid, HC2H3O2 and hence its 0.1 M solution should have a conductivity value, greater than HC2H3O2.
Therefore, correct answer is option A).