Lab Report: Solubility and Acid-Base Properties of Organic ...



Lab Report: Solubility and Acid-Base Properties of Organic Compounds (Exp. 2) 40 pts/max

NAME: Shawn Vuong SECTION: 145

Part 4: Classification of an Unknown Organic Compound by its Acid/Base Properties.

Unknown Number: #6

Identity of Unknown (alkane, alcohol, amine, or carboxylic acid):

(Amine (10 pts)

Experimental Evidence: The compound was non soluble in water. When put on blue indicator paper, paper stayed blue. When put on red indicator paper, paper stayed red. This suggested that the unknown organic compound was both, non polar and neutral. Then compound did not dissolve in 10% hydrochloric acid or in 10% aqueous sodium hydroxide. Finally added compound to the concentrated sulfuric acid and compound turned a copper color and bubbled. Also the reaction gave off heat. This was similar to the reaction in part 3 with dimethylaniline and the concentrated sulfuric acid. (20 pts)

Question. para-Cresol has low solubility in water but is much more soluble in 10% NaOH (aq). On the other hand anisole, an isomer of para-cresol, has low solubility in both water and 10% NaOH (aq). Give a reasonable explanation to account for these observations.

(10 pts)

( Both para-cresol and anisole must be non-polar molecules, or not polar enough to dissolve in water fully dissolve in water. But in para-cresol the OH group makes the molecule acidic, which causes it to dissolve in a base. On the other hand anisole has the methyl group in place of the hydrogen in its isomer para-cresol. Therefore it will not be giving up any hydrogen and will not be acidic and as a result does not dissolve in the basic solution sodium hydroxide.

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