Simple distillation boiling stones

Liquids in solution are often separated based on their boiling point differences. During simple distillation, the solution is placed in a round-bottom flask called the distillation flask or still pot, and boiling stones are added. The apparatus shown below is assembled (note that clamps and stands are not shown), and the still pot is heated using a heating mantle. 

For either the simple or fractional distillation, place a boiling stone into the 10-mL round-bottom flask. Also add 8.0 mL of the unknown mixture (measured with a 10-mL graduated cylinder) to the flask. Use a hot plate and an aluminum block for heating. 

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