Molar conductivity of coordination compound The compound is $\ce{[Cr(H2O)6]Cl3}$. Which isomer has least molar conductivity ?
Correct answer : $\ce{[Cr(H2O)4Cl2]Cl.2H2O}$
My answer : $\ce{[Cr(H2O)3Cl3].3H2O}$
Molar conductivity is directly proportional to the number of ions on dissociation. If number of ions is same, the one with more net charge  has more molar conductivity. Therefore the compound I stated should have least molar conductivity as the only dissociation it undergoes is separation of coordination entity from water molecules. As none of them are charged ions, they wont increase molar conductivity. What is wrong with my concept ?
You are right. But for some reason, your compound has never been synthesized, although theoretically ti should exist. It may be a problem of entropy.