The following figure is a typical crystallization set-up of benzoic acid. In which container the benzoic acid crystals will be formed? questions (2024)

Experiment: Extraction to seperate benzoic acid andnaphthalene.

Procedure-

Place 2 g of a 1:1 (by weight) mixture of benzoic acid andnaphthalene in a small beaker; record the exact mass of the mixturein your notebook. Add 35 mL of dichloromethane to the beaker andstir until the solid mixture has completely dissolved. Carefullypour the solution into a separatory funnel.

Add 20 mL of 3.0 M NaOH to the separatory funnel, stopper it,and shake the mixture with frequent venting. When the layers haveseparated, drain the bottom portion into a clean flask. Pour theaqueous layer into another clean flask labeled “aqueous layer.”Pour the organic layer back into the separatory funnel and extractwith a second portion of 3.0 M NaOH. Drain the bottom layer into aclean flask labeled “organic layer” and pour the aqueous layer intothe “aqueous layer” flask.

Put the organic layer back into the separatory funnel and shakewith 20 mL of saturated NaCl solution. Drain the organic layer intoa clean, dry flask and add a small amount of anhydrous calciumchloride to dry the solution. Allow this solution to stand for atleast ten minutes, with occasional swirling, then remove the dryingagent by gravity filtration; place the filtrate in a round-bottomflask and remove the solvent by simple distillation or by using therotovap. Once the dichloromethane has been removed, scrape thecrystals out of the round-bottom flask into a clean, labeled, taredvial, and determine the weight and melting point of the naphthalenecrystals.

Acidify the combined aqueous layers with 6.0 M HCl until thesolution tests acidic to litmus paper. A white precipitate ofbenzoic acid should develop as the solution is neutralized. Chillthe solution in an ice bath for at least ten minutes to finishprecipitating the solids, then collect the benzoic acid by vacuumfiltration. Wash the crystals with a small amount of cold water;then scrape the crystals into a clean, labeled, tared vial andallow to dry. Once the crystals are dry, determine their weight andmelting point.

Post-Lab Question:

Write a balanced equation (using structures) for thereaction that takes place when the aqueous layer is acidified withHCl. Why does the precipitate form when the solution isneutralized? (HINT: benzoic acid (slightly soluble in water) andsodium benzoate (soluble in water)

You did a reaction and it resulted in the following mixture ofcompounds:

(Benzoic ring, benzoic ring with OH, Benzoic ring with COOH)

What would you do to isolate and then purify benzoic acid?

How would you prove that your final product is pure?

Which peaks in the IR and NMR you would look for to see if yougot indeed benzoic acid? Mention all, but also specify the peaksthat are different from peaks the other compounds have aswell.

In order to know about solubility for caffeine andbenzoic acid, I put caffeine and benzoic acid in water and HCl andNaOH, and Caffeine was miscible in NaOH and Benzoic acid wasmiscible in HCl.

1. could you explain me why?

2. How would you know if caffeine and benzoic acid areacid or base?

Suppose a 0.050 M benzoic acid, HC7H5O2 solution is prepared.The Ka for benzoic acid is 6.3×10 −5. Calculate the pH of thebenzoic acid solution.

pH = ?

The Separation of Three Organic Compounds by Acid, BaseReactions and Liquid, Liquid Extraction.

Okay, so we had solid benzoic acid, ethyl 4- aminobenzoate, and9-fluorenone all dissolved in diethyl ether. We separated the basiccomponent by adding 3M HCl, we separated the acidic component byadding 3M NaOH. I don't understand what happens here. To isolatethe acidic solution, we added 6 M NaOH and used the vacuum torecover the solid. To isolate the basic solution we added 6M HCl. Idid an experiment where a 1:1:1 mixture of Benzoic Acid solid(C6H5COOH), ethyl 4-aminobenzoate solid (C9H11NO2), and9-fluorenone solid (C13H8O) was dissolved with methylene chloride.Then each component was extracted and tested. I need to come upwith a proton transfer chemical reaction that represents whathappened in each separation. First separation: HCl was added andtwo layers formed. aqueous layer was extracted and transfer to aclean container and methylene chlotide layer was left aside. NaOHwas added dropwise to aqueouse layer extraction and vacuumfiltration was used to extract/separate the basic component ethyl4-aminobenzoate solid (C9H11NO2).

Results &Data:

1)Benzoic acid (Acid)

Table 1: Collected data from Benzoic acid

2) Benzoate (Base)

Table 2: Collected data from Benzoate.

3) 9-Fluorenone (Neutral)

Table 3: Collected data from 9-Fluorenone.

I need to find the theoretical and percent yield of eachproduct, how many mg of each product is present. And also create 4chemical reactions. Need help, Please help thankyou

1. Calculate [OH−] for a solution formed by adding 5.00 mL of0.120 M KOH to 20.0 mL of 7.1×10⁻² M Ca(OH)2.

2. Calculate pH for a solution formed by adding 5.00 mL of 0.120M KOH to 20.0 mL of 7.1×10⁻² M Ca(OH)2.

3. Pyridine is a weak base that is used in the manufacture ofpesticides and plastic resins. It is also a component of cigarettesmoke. Pyridine ionizes in water as follows:

C5H5N+H2O⇌C5H5NH++OH−

The pKb of pyridine is 8.75. What is the pH of a 0.430Msolution of pyridine?

4. Benzoic acid is a weak acid that has antimicrobialproperties. Its sodium salt, sodium benzoate, is a preservativefound in foods, medications, and personal hygiene products. Benzoicacid dissociates in water:

C6H5COOH⇌C6H5COO−+H+

The pKa of this reaction is 4.2. In a 0.79 Msolution of benzoic acid, what percentage of the molecules areionized?

Given the following information:

benzoic acid = C6H5COOH

hydrocyanic acid = HCN

C6H5COOH is a stronger acid than HCN

(1) Write the net ionic equation for thereaction that occurs when equal volumes of 0.052 M aqueousbenzoic acid and sodium cyanideare mixed. It is not necessary to include states such as (aq) or(s).

_______ + _______ = _________ + _________

(2) Which is the strongest base, C6H5COO- or CN- ?

(3) At equilibrium the products or reactantswill be favored????