How do you separate benzoic acid from a mixture of CONGO RED and salt?

Answer 1

Dissolve the mixture in an apolar organic solvent, such as diethyl ether, and extract the acid with the addition of NaOH. The bezoic acid with ionize and go into the aqueous solution. Separate the two layers and add HCl to the aqueous layer to precipitate the benzoic acid. Wash the remaing ether solution with water and dry it with an anhydrous salt. Filter the ether solution and then remove the ether, the solvent, in order to obtain the pure benzoin.

Answer 2

Both benzoic acid and biphenyl are organic solutes, and therefore will dissolve in organic solvents. (ie: diethyl ether)

Benzoic acid (an acid) will react with a strong base (ie: NaOH) to form sodium benzoate (which is a water soluble salt) and aqueous NaCl.

Therefore, if you have a mixture of biphenyl and benzoic acid, you can dissolve it in an organic solvent (say diethyl ether) and add NaOH, to convert benzoic acid into a water soluble salt. (water is NOT soluble in organic solvents). therefore your mixture in solution will separate into two layers. The upper organic layer will contain biphenyl dissolved in ether, and the lower aqueous layer will contain the water soluble salt of benzoic acid and water. (as well as aqueous NaCl).

Using a separatory funnel, or other separation equpiment, the two layers can be separated.

The benzoic acid can be extracted by adding HCl which will convert the salt back into benzoic acid, and the solution can be chilled (to cause precipitation of benzoic acid) and then filtered by suction filtration, etc..

The biphenyl can be extracted by distillation, as ether is quite volatile and will evaporate easily (B.pt = 34.6 degrees Celsius)

Answer 3

Well benzoic acid is quite lipophilic, so you can extract the acid from an inorganic salt (or it's aqueous solution) with the aid of an organic solvent e.g. ether, MTBE or something similar.

After evaporation of the solvent you should have quite pure benzoic acid, which can be further purified by recrystallization with hot water and some norit/active carbon or you dissolve it in some lye and on acidification with some (hydrochloric/sulfuric/etc.) acid it can be precipitated, washed with water and dried.

Answer 4

Add water and after the solving of benzoic acid filter the solution; on the filter remain the sand and the solution is a solution of benzoic acid. But this experiment is without sense.

Answer 5

It can be separated by Crystallization and decolorization. It is because the benzoic acid is soluble in hot water. If the hot solution is cooled, the benzoic acid will recrystallize.

Answer 6

Liquid-Liquid extraction is the technique commonly used. This is where two immiscible fluids are used, an organic phase and aqueous phase.

Answer 7

Add water which will dissolve the salt. Filter out the benzoic acid crystals which are barely soluble. Dry the benzoic acid crystal. Evaporate the water of the salt solution by boiling. Dry.

Answer 8

evaporate it