How many moles of sucrose should be dissolved in 500gms of water so as to get a solution which has a difference of 104^(@)C between boiling point and freezing point. (K_(f)=1.86 K Kg "mol"^(-1).K_(b)=0.52K Kg "mol"^(-1))

How many moles of sucrose should be dissolved in 500gms of water so as

1.	How many moles of sucrose should be dissolved in 500gms of water so as to get a solution which has a difference of 104^(@)C between boiling point and freezing point. (K_(f)=1.86 K Kg "mol"^(-1).K_(b)=0.52K Kg "mol"^(-1))
Answer» `1.68` `3.36` `8.40` `0.840` Solution :Boiling POINT of solution `=` boiling point `+DeltaT_(B)=100+DeltaT_(b)` Freezing point of solution `=` Freezing point `-DeltaT_(f)=0-DeltaT_(f)` Diffrence in temperature (given) `=100+DeltaT_(B)-(-DeltaT_(f))` `104=100+DeltaT_(b)+DeltaT_(f)=100+"molality"xxK_(b)+"molallity"xxK_(f)` `=100+"molality"(0.52+1.86)` `therefore "Molality"=(104-100)/(2.38)=(4)/(2.38)=1.68m` and molality `=("moles"xx1000)/(W_(gm(solvent))),1.68=("moles"xx1000)/(500)` `therefore` Moles of SOLUTE `=(1.68xx500)/(1000)=0.84` moles.