Question

Identify the binary mixture(s) that can be separated into the individual compounds, by acid-base differential extraction, as shown in the given scheme. \begin{tabular}{|l} \(\qquad\) Aq. NaOH Binary mixture \\ \(\qquad\) Aq. \(\mathrm{NaHCO}_{3}\) \(\longrightarrow\) Compound \(1+\) Compound 2 \end{tabular} (A) \(\mathrm{Ph}-\mathrm{OH}\) and \(\mathrm{Ph}-\mathrm{COOH}\) (B) \(\mathrm{Ph}-\mathrm{CH}_{2}-\mathrm{OH}\) and \(\mathrm{Ph}-\mathrm{SO}_{3} \mathrm{H}\) (C) \(\mathrm{CH}_{3}-\mathrm{COOH}\) and \(\mathrm{CH}_{3}-\mathrm{OH}\) (D) \(\mathrm{Ph}-\mathrm{CH}_{3}\) and \(\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{COOH}\)

Short answer

All the given binary mixtures (A, B, C, and D) can be successfully separated into individual compounds using the provided acid-base differential extraction scheme.

Step-by-step solution

Identify functional groups of each compound

: We will begin by identifying the functional groups present in each compound provided. (A) \(\text{Ph}-\text{OH}\) and \(\text{Ph}-\text{COOH}\): - \(\text {Ph}-\text{OH}\): Phenol (an aromatic compound containing an alcohol group) - \(\text{Ph}-\text{COOH}\): Benzoic acid (an aromatic compound containing a carboxylic acid group) (B) \(\text{Ph}-\text{CH}_2-\text{OH}\) and \(\text{Ph}-\text{SO}_3\text{H}\): - \(\text{Ph}-\text{CH}_2-\text{OH}\): Benzyl alcohol (an aromatic compound containing an alcohol group) - \(\text{Ph}-\text{SO}_3\text{H}\): Benzenesulfonic acid (an aromatic compound containing a sulfonic acid group) (C) \(\text{CH}_3-\text{COOH}\) and \(\text{CH}_3-\text{OH}\): - \(\text{CH}_3-\text{COOH}\): Acetic acid (a carboxylic acid) - \(\text{CH}_3-\text{OH}\): Methanol (an alcohol) (D) \(\text{Ph}-\text{CH}_3\) and \(\text{CH}_3-\text{CH}_2-\text{COOH}\): - \(\text{Ph}-\text{CH}_3\): Toluene (an aromatic compound) - \(\text{CH}_3-\text{CH}_2-\text{COOH}\): Propanoic acid (a carboxylic acid)

Understand the behavior in acid-base extraction

: We now analyze how each of these functional groups behaves when exposed to the NaOH and NaHCO3 phases during the acid-base extraction process: 1. Alcohols typically don't react with either NaOH or NaHCO3. 2. Carboxylic acids will react with both NaOH and NaHCO3 to form salts. 3. Sulfonic acids will react with both NaOH and NaHCO3 to form salts. 4. Aromatic compounds (with no additional acidic groups) will not react with either NaOH or NaHCO3.

Evaluate the mixtures to identify the ones that can be separated

: Based on the functional groups and their behaviors, let's assess if the binary mixtures can be separated into their individual compounds using the given extraction scheme. (A) \(\text{Ph}-\text{OH}\) and \(\text{Ph}-\text{COOH}\): - Phenol will not form a salt with either NaOH or NaHCO3. - Benzoic acid will form a salt with both NaOH and NaHCO3. - This mixture can be separated by the given extraction process. (B) \(\text{Ph}-\text{CH}_2-\text{OH}\) and \(\text{Ph}-\text{SO}_3\text{H}\): - Benzyl alcohol will not form a salt with either NaOH or NaHCO3. - Benzenesulfonic acid will form a salt with both NaOH and NaHCO3. - This mixture can be separated by the given extraction process. (C) \(\text{CH}_3-\text{COOH}\) and \(\text{CH}_3-\text{OH}\): - Acetic acid will form a salt with both NaOH and NaHCO3. - Methanol will not form a salt with either NaOH or NaHCO3. - This mixture can be separated by the given extraction process. (D) \(\text{Ph}-\text{CH}_3\) and \(\text{CH}_3-\text{CH}_2-\text{COOH}\): - Toluene will not form a salt with either NaOH or NaHCO3. - Propanoic acid will form a salt with both NaOH and NaHCO3. - This mixture can be separated by the given extraction process. So, all the given binary mixtures (A, B, C, and D) can be successfully separated into individual compounds using the provided acid-base differential extraction scheme.

Key concepts

Functional Groups Identification

In chemistry, identifying functional groups is crucial for understanding how molecules will react. A functional group is a specific group of atoms within a molecule that is responsible for a characteristic reaction of that molecule. For instance:

• Phenols like \(\text{Ph}-\text{OH}\) contain an -OH group attached to an aromatic ring.
• Carboxylic acids, such as \(\text{Ph}-\text{COOH}\), have a carboxyl group \(-\text{COOH}\).
• Alcohols, like \(\text{Ph}-\text{CH}_2-\text{OH}\), contain an -OH group but are not aromatic.
• Sulfonic acids, like \(\text{Ph}-\text{SO}_3\text{H}\), contain a sulfonic group \(-\text{SO}_3\text{H}\).

Understanding these groups helps chemists predict how different substances will interact in chemical reactions.

Reactivity with NaOH and NaHCO3

Acid-base reactions are fundamental in chemistry, serving as an important separation technique. When compounds are mixed with bases like NaOH and NaHCO3, their reactions center around their acidity:

• Alcohols typically don't react with these bases, as they are weak acids.
• Carboxylic acids will react, forming salts with both NaOH and NaHCO3 due to their acidic nature.
• Sulfonic acids are stronger acids and will also react readily with these bases to form corresponding salts.
• Aromatic compounds without acidic groups, such as toluene, will not form salts or react significantly.

This differential reactivity is key to separating compounds based on their acid-base properties.

Separation of Binary Mixtures

The process of separating compounds through acid-base differential extraction relies on the differing solubilities of salts and neutral compounds:

• Compounds that form salts with bases become water-soluble, while neutral compounds remain in the organic phase.
• For example, in a mixture of a carboxylic acid and an alcohol, the acid reacts with the base, forming a water-soluble salt, which can then be separated from the non-reactive alcohol.
• Recovery of the acid is achieved by treating the aqueous phase with a stronger acid, whereas the alcohol stays in the organic layer.

This approach is particularly useful for separating mixtures of acidic and neutral compounds.

Alcohols and Carboxylic Acids

Alcohols and carboxylic acids are two important functional groups with unique properties:

• Alcohols, even though they contain -OH groups, do not possess strong enough acidity to react with bases like NaOH and NaHCO3.
• Carboxylic acids, with their stronger acidity due to the presence of the carboxyl group, will react with both NaOH and NaHCO3, forming salts.
• This difference in reactivity allows for effective separation in mixtures, where carboxylic acids can be selectively converted and isolated.

Understanding the behavior of these groups in chemical reactions helps in the manipulation and separation of complex mixtures.

Sulfonic Acids Behavior

Sulfonic acids are strong acids due to the presence of the sulfonic group:

• Unlike most organic acids, they are strong enough to react with basic solutions like NaOH and NaHCO3, even in dilute form.
• This reactivity helps in their conversion to water-soluble salts, facilitating their separation from non-acidic counterparts in a mixture.
• Their behavior is similar to that of mineral acids, making them highly effective in acid-base extraction processes.

Sulfonic acids' distinguished acidic nature plays a critical role in differential extraction, allowing for their easy separation and isolation in chemical processes.