Solution

option D

let x is the mole required of sucrose.
As we know the normal freezing and boiling point of water is 0 and 100 degreeC respectively.molality of sucrose=(x/500)1000=2x
Now calculate the final boiling point:
T1’.........=...........T1......+....Kb2x
and the final freezing point:
T2’.........=...........T2......+....Kf*2x
where T1=100 degree
T2=0 degree
now, according to question,
T1’T2’=104
now calculate value of x.