When 20 gm optically active compound is placed in a 10 dm tube, in a 200 ml solution rotates the PPL by `30^(@)` :
(a) What is the angle of rotation if above solution is dilute to 1 litre ?
(b) What is the specific angle of rotation if above solution is diluted to 1 litre ?

Answer

630

Explanation

Mass = 20 gm
Volume = 200 ml
`C=(mass)/(volume)=20/200=0.1gm//ml`
Length of tube (l) = 10 dm
Optical rotation `theta=30^(@)`
`" "alpha=(theta)/(Cxxl)`
`" "alpha=30/(0.1xx10)=30`
(a) If solution is dilute to one litre then volume
V= 1000 ml
`theta`=?
`alpha=(theta)/(Cxxl),30=(theta)/(20/1000),theta=6^(@)`
(b) Specific rotation does not change with change in conc. or volume of length etc. therefore it is `30^(@)`