Question

How many mmol of sucrose should be dissolved in 500 gms of water so as to get a difference of 103.57° between boiling an freezing point?

Answer 1

let x be milimole of sucrose dissolve in 500gm water ,so moles will be x*(10^-3) molarity=x(10^-3) / 500(10^-3) = x/500 from here Tb=100+.52 x/500 Tf-0 =1.86 x/500 from here Tf=1.86 x/500 given Tb – Tf=103.57 =100+.52 x/500 +1.86 x/500 from here by solving u will get x=750 mili moles.