CBSE Class 12-science Answered

Dear Student

 Let us call the rotations caused bu solutions per unit column length = R

Rotation caused by solution 1 per unit length  R1=  32/20=1.6

Rotation caused by solution  2 per unit length  R2=  24/30=0.8

If we consider 1:4 mixture  

Contribuition of solution 1 in the mixture = 1/ (1+4)  = 0.2

Contribuition of solution 2 in the mixture = 14 (1+4)  = 0.8

Rotation per unit length of  mixture  =  (0.2 X1.6)  +   (0.8X0.8) =0.96

optical rotation caused by 25cm length of a mixture of the above solutions in the volume ratio 1:4

=25X 0.96=  24⁰

Regards

Team

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