A certain mass of a substance when dissolved in 100 g C6H6 lowers the freezing point by 1.28°C. The same mass of solute dissolved in 100 g of water lowers the freezing point by 1.40°C. If the substance has normal molecular mass in benzene and is completely dissociated in water, into how many ions does it dissociate in water? Kf for H2O and C6H6 are 1.86 and 5.12 K mol-1 kg respectively.