A mixture of benzoic acid , aniline and phenol is dissolved in chloroform and the solution is treated with NaOH, HCl , and NaHCO3 . Show a separation chart , identify the composition of each phase and explain the chemistry of the separation process.
This site does not support diagrams; therefore, I can't draw a flow diagram/separation chart. Here is what you do; you will need to take this information and make your own chart.
1. Treat with HCl. That will dissolve the aniline and the aniline:HCl salt will dissolve in the water layer. I assume you can write the equation. Place the solution in a separatory funnel. The chloroform layer will contain the benzoic acid and phenol.
2. Add NaHCO3 to the CHCl3 layer. Benzoic acid is a strong enough acid it will form a salt with NaHCO3. The phenol will not react. Write an equation for the benzoic acid + NaHCO3. That salt will be soluble in water but the phenol will remain in the chloroform layer. Place in a sep funnel and separate the two layers.
3. Adding NaOH will form a salt with the phenol.
I hope this helps.
To illustrate the separation of a mixture of benzoic acid, aniline, and phenol dissolved in chloroform using NaOH, HCl, and NaHCO3, we can create a separation chart, identify the composition of each phase, and explain the chemistry behind the separation process.
The separation chart would look like this:
| Compound | Chloroform Phase | Aqueous (Water) Phase |
|-------------|------------------|----------------------|
| Benzoic acid| No | Yes |
| Aniline | Yes | Yes |
| Phenol | Yes | Yes |
Explanation of the separation process:
1. Addition of NaOH:
- Benzoic acid is a weak acid and reacts with NaOH to form sodium benzoate, which is soluble in water. The reaction is as follows:
Benzoic acid + NaOH → Sodium benzoate + H2O
- Aniline and phenol are not affected by NaOH and remain in the organic (chloroform) phase.
- So, after adding NaOH, the benzoic acid is converted into the water-soluble sodium benzoate and is present in the aqueous phase, while aniline and phenol continue to be in the organic phase.
2. Addition of HCl:
- Sodium benzoate, being a salt, reacts with HCl to form benzoic acid again. The reaction is as follows:
Sodium benzoate + HCl → Benzoic acid + NaCl
- Benzoic acid, being a weak acid, remains in the organic phase (chloroform) due to its low solubility in water.
- Aniline and phenol are not affected by HCl and continue to remain in the organic phase.
3. Addition of NaHCO3:
- Phenol and benzoic acid react with NaHCO3 to form their respective sodium salts, which are water-soluble. The reactions are as follows:
Benzoic acid + NaHCO3 → Sodium benzoate + CO2 + H2O
Phenol + NaHCO3 → Sodium phenolate + CO2 + H2O
- Aniline is not affected by NaHCO3 and remains in the organic phase.
- After adding NaHCO3, both benzoic acid and phenol are converted into their respective sodium salts and are now present in the aqueous phase, leaving aniline in the organic phase.
Therefore, at the end of the separation process, benzoic acid and phenol are present in the aqueous phase as sodium benzoate and sodium phenolate, respectively, while aniline remains in the organic (chloroform) phase.
To create a separation chart for the given mixture of benzoic acid, aniline, and phenol dissolved in chloroform, and treated with NaOH, HCl, and NaHCO3, we need to understand the chemistry behind the separation process and the properties of each component.
Separation Chart:
Phase 1: Organic Phase (Chloroform)
- Contains benzoic acid, aniline, and phenol
Phase 2: Aqueous Phase (NaOH, HCl, NaHCO3 solutions)
- Contains the separated components: benzoic acid, aniline, and phenol
Chemistry of the Separation Process:
The separation process of benzoic acid, aniline, and phenol involves using the different acid-base properties of these substances. Let's look at each step:
1. Addition of NaOH Solution:
- Benzoic acid reacts with NaOH to form sodium benzoate, which is a soluble salt:
Benzoic acid + NaOH → Sodium benzoate + H2O
- Aniline reacts with NaOH to form a water-soluble salt:
Aniline + NaOH → Aniline salt + H2O
- Phenol does not react with NaOH, and remains unchanged.
After the addition of NaOH, all the substances that have reacted are converted into water-soluble salts, while phenol remains in the organic phase.
2. Separation of Organic Phase and Aqueous Phase:
- The organic phase (chloroform) contains phenol, while the aqueous phase contains the water-soluble salts of benzoic acid and aniline.
- To separate the two phases, you would typically use a separating funnel. The organic phase, being denser, will settle at the bottom, while the aqueous phase will be above it.
3. Acidification with HCl Solution:
- Sodium benzoate (from benzoic acid) reacts with HCl to regenerate benzoic acid:
Sodium benzoate + HCl → Benzoic acid + NaCl
- The regenerated benzoic acid is now insoluble in the aqueous solution and will precipitate out.
4. Separation of Precipitated Benzoic Acid:
- Filtering or centrifuging the mixture will separate the solid benzoic acid from the aqueous phase containing the salts of aniline.
- The solid benzoic acid can be collected, while the aqueous phase is retained for further separation.
5. Neutralization with NaHCO3 Solution:
- The remaining aqueous phase, containing aniline salts, is now treated with NaHCO3.
- Aniline salts react with NaHCO3 to form aniline, which is insoluble in the aqueous solution:
Aniline salt + NaHCO3 → Aniline + NaHCO3 salt
- The insoluble aniline is now separated from the aqueous phase.
After completing these steps, you will have separated the three components of the mixture: benzoic acid, aniline, and phenol. Benzoic acid will be obtained as a solid precipitate, aniline will be isolated as a separate compound, and phenol will remain in the organic phase (chloroform).
Note: It is important to understand that the separation process described here provides a general outline. In a lab setting, other factors like temperature, concentration, and purification techniques may need to be considered for an efficient separation.