UPSEE 2017 Solved Paper

∵6% sucrose solution is isotonic with 3% solution of unknown organic substance, thus,
π(suctose) =π(otganic substance)
or CRT(sucrose) =CRT(organice substance)
or [

W

M×V

.RT](sucrose) =[

W

M×V

.RT](organic substanoe)
or

6

342

=

3

M(organic substance)

where, W(suctose) =6
W(organic substance) =3
M(sucrose) =342
M(organic substance) =?
Hence, M(organic substanoe) =

3×342

6

∴ Molecular mass of unknown organic substance=171
Note - The formula of sucrose in the question is given C22H22O11, which is incorrect. The correct formula is C12H22O11.