COMEDK Exam 2019 Solved Paper

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
‌=‌

160

200

×100%
‌=80%