Given, specific rotation of sugar solution, α=0.01 units Length of polarimeter tube, l=0.25m Optical rotation, θ=0.4rad Concentration of solution, c= ? As we know, specific rotation =
Optical rotation
Length of tube × Concentration of sol.
α=
θ
l×c
c=
θ
l×α
=
0.4
0.01×0.25
=160kg∕m3 Concentration of sugar solution =200kg∕m−3 (given) Percentage impurity of sugar in the sample =