Is a compound optically active if plane polarised light is deflected by an angle of n*(2π) angles? [closed]








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Is a compound optically active if plane polarised light is deflected by an angle of n\*(2π) angles(like 360°); as there won't be any deflection in the analyser of the polarimeter?




**Yes**


The actual rotation you observe in a polarimeter depends on several factors: the path length, the concentration (if in solution) and the specific amount of optical rotation caused by the compound.


If you observe the actual rotation at a single concentration you might observe no *apparent* effect because the rotation was 360°. But at a different concentration or a different path length with the same substance you *would* observe a rotation.


So it is pretty easy to avoid the mistake of assuming no rotation by simply taking more than one measurement while varying the other factors.


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