KEAM 2011 Physics and Chemistry Paper

since the two solutions are isotonic, they must have same concentrations in moles\/litre.
For glucose solution, concentration
=5g/100cm3 (given)
=50g/L
=‌

501

180

moles /L
( ∵ Molar mass of glucose =180gmol−1 )
For unknown substance, concentration
=2g/100cm3 (given)
=20g/L=‌

20

M

mol/L
∴‌‌‌

50

180

=‌

20

M

or M=72