Ask A Scientist© Environmental Earth Science Archive

name         Sheryl
status       other
grade        other
location     N/A

Question -   What are the uses of refractive index in Chemical
Engineering?
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I suppose it is mostly a property of mixtures
which can be measured to give a quick diagnostic indication
about the composition your chemical stock.
I certainly have seen a lot of refractometers in catalogs,
calibrated in "Brix scale" to tell the cook how dense her sugar-water is.
That kind of thing...

Refractive index does not actually affect chemical behavior much,
because light does not usually influence reactions,
and because index influences the fate of light rather little
compared with absorption.

But in physical theory, index is partly related to dielectric permeability
and to cohesion between non-polar molecules.
Liquid Xenon has a higher refractive index than Liquid Helium,
and also has a higher boiling point.
Those two aspects are somewhat related,
and occasionally it is nice to understand that.
A heavier solvent probably has a higher refractive index,
and vice/versa.

Jim Swenson
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Sheryl,

One use that the refractive index can be used for in Chemical Engineering 
is finding out the purity of the chemical in question that is being 
analyzed. I hope that this helps.

Sincerely,
Bob Trach
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