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.

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Infinity Learn · Accepted Answer

Δ$$Tf=1000$$×Kj′×wm×WFor the solution in benzene using the data given $$1.28=1000$$×$$5.12$$×wmN×$$100mN=$$ normal mol. mass … $$($$ $$i)For$$ the solution in water in which solute dissociates $$1.40=1000$$×$$1.86$$×wmexp. ×$$100$$       . . .  (ii)dividing$$ e.q. $$(ii) by $$(i)i=mNmexp=1.401.28$$×$$5.121.86=3.01=3.0Now$$, suppose that formula of solute isAxBy⇌$$xA++yB$$−$$100(1$$−α$$)x$$αyα∴ $$i=1$$−α$$+x$$α$$+y$$α

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