question_answer

A certain mass of a substance when dissolved in 100 g of benzene\[\left( {{C}_{6}}{{H}_{6}} \right)\], lowers the freezing point by \[{{1.28}^{o}}C.\]The same mass of solute dissolved in 100 g of water lowers the freezing point by \[{{1.40}^{o}}C.\] If the substance has normal molecular weight in benzene and is completely ionised in water, into how many ions does it dissociate in water? \[[{{K}_{f}}({{H}_{2}}O)=1.86K\,\,kg\,\,mo{{l}^{-1}}and\,\,{{K}_{f}}({{C}_{6}}{{H}_{6}})=5.12kg\,\,mo{{l}^{-1}}]\]

A)  1           

B)  2             

C)  3          

D)  4