What is the difference between the (R) -2-butanol and (S) -2-butanol? Describe the phenomenon of optical isomerism by using terms such as chirality, asymmetric (stereogenic) center, enantiomers etc.

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2-butanol is a clear, organic, secondary alcohol.  That means the hydroxyl group is attached to the second carbon atom.  The difference in the R-2-butanol and the S-2-butanol has to do with the positioning of the hydroxyl group on the second carbon atom.  The R group has the hydroxyl group leaning forward in a three dimensional model, while the S group has the hydroxyl group receding, leaning in a backwards fashion, in a three dimensional model.

The two forms of butanol are chiral enantiomers of each other, meaning they are non-superimposable mirror images of each other.  They are also optical stereoisomers, meaning they are the same chemical composition, but with a different placement of the atoms, the key difference being the positioning of the hydroxyl group.  The center of the group is asymmetric, having four carbon atoms, with the hydroxyl group on carbon atom two.  Both versions of the stereoisomers are found in equal proportions, making them a racemic mixture.

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The difference between R-2-butanol and S-2-butanol is the positioning of the hydroxide group on the second carbon atom.  The "R" version has the hydroxide group coming forward in a model, while the "S" version has the hydroxide group going backward in a model.  Both versions make the molecule chiral, meaning there is a non-superimposable mirror image version of it.  The two different versions are called stereoisomers, meaning they are essentially the same composition except for the positioning of the hydroxide group.  Such groups of molecules are said to be enantiomers, or optical isomers.  They are also referred to as "right-handed" or "left-handed."  It is also a racemic mixture, meaning there are equal parts of the right or left handed version.

2-butanol is an organic secondary alcohol that is soluble in water to some degree, but completely miscible with other organic compounds, such as ether and other alcohols.  It is used primarily as a mineral spirit and solvent in paint removers.

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