Benzoic Acid Essay

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Extraction of Benzoic Acid Experimental 4.08 g of crude benzoic acid mixture was weighed and placed in a 125 mL Erlenmeyer flask. Then 50 mL of diethyl ether was added into the 125 mL Erlenmeyer flask. Some boiling stones were added before heating the mixture on a steam bath. After the ether began to boil, the ether insoluble material was removed from the ether solution using the technique of Buchner funnel vacuum filtration. Then the filtrate was placed in a 500 mL separatory funnel and 30 mL of 1M NaOH was added into the separatory funnel. The lower aqueous layer was drained into a 250 mL flask. Another 30 mL of 1M NaOH was added into the separatory funnel, and the lower aqueous layer was darined again into the flask that already had the first aqueous extraction. Then the combined aqueous extraction solutions were cooled on ice, following that 50 mL of 6 M HCl which had also been cooled on ice was added into the combined aqueous extraction. The solid precipitate was collected by using vacuum filtration technique. Finally, the collected crystals in the Buchner funnel were weighed on a weighed watch glass. Results 4.08 g of crude benzoic acid mixture was weighed. The solution turned dark pink when the diethyl ether was added into the flask with crude benzoic acid mixture in it. After processing first vacuum filtration, some pinkish solids were trapped in the Buchner funnel. When using the separatory funnel to extract, the filtrate was separated into two layers (Figure 1). Finally, pinkish precipitates appeared after acidifying the cooled combined aqueous extraction solutions with 6M HCl. Total weight of the pinkish crystal was 12.4g. The percent composition was calculated as: % of Benzoic Acid= Final mass of impure Benzoic AcidOriginal mass of Benzoic Acid Mixture × 100% =12.4g4.08g ×100%=303.92% Organic Layer Aqueous Layer Figure 1:
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