[BluePill]

Here's the question:

Suppose you place a sample of sugar in a polarimeter and observe a rotation of 90 degrees, how can you be sure the sample isn't rotating the plane of pol light by -270 degrees( both would give the same reading on polarimeter)
propose a way (in theory or experiment) that you could discern between these possibilities

I'm thinking of hydrolyzing it then look at the rotation after hydrolysis. Is that correct?

[Borek]

What should happen if you dilute the solution?

[BluePill]

Observed rotation would decrease right?

[BluePill]

I find the question a little vague as well. My first interpretation was my answer and another was a mixture of enantiomers. But I got your point Borek.