Solubility is the chemical property which refers to how much a solute will dissolve in the solvent. Polar compounds dissolve better in polar solvents, while non-polar compounds dissolve better in non-polar solvents. This is why the best solvent in the experiment for non-polar benzil is hexane because it is also non-polar. In addition, non-polar compounds have lower melting points since electronegativity is lower.
The first part of the experiment was spent finding the best solvent. It had to be insoluble at room temperature, soluble at boiling point, and crystalize in ice. Hexane was found to be the best solvent.
The next part of the lab was to recrystallize phthalic acid. It was dissolved in water, boiled, then placed in an ice bath to crystallize. Once the crystals formed, it was filtered to separate the impurities from the compound. Finally, recrystallization had to be performed for the unknown 6 and then calculate the melting point. The same procedure used to recrystallize and filter the phthalic acid was used for the unknown 6. The crystals were left to dry for five days and measured. The melting point of unknown 6 was 96 degrees celsius, which concluded to be benzil.
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