Question

Question: Acetic acid is miscible with water. Would you expect carboxylic acids with the general formula ${\mathbf{CH}}_{\mathbf{3}}{\left({\mathbf{CH}}_{\mathbf{2}}\right)}_{\mathbf{n}}\mathbf{COOH}$to become more or less water-soluble as n increases? Explain.

Short answer

Answer

As n increases, ${\mathbf{CH}}_{\mathbf{3}}{\left({\mathbf{CH}}_{\mathbf{2}}\right)}_{\mathbf{n}}\mathbf{COOH}$the solubility of carboxylic acids with the general formuladecreases.

Step-by-step solution

Solubility 

Solubility is the process of mixing a solute into a solvent, making a homogeneous mixture. The main condition for solubility is like dissolves which mean polar solute can be dissolved in a polar solvent and vice versa.

Carboxylic acids have a non-polar hydrocarbon chain and a polar head which can interact with the water molecules making them miscible in water.

 Step 2: Decreasing solubility on increasing n

As n increases, the non-polar hydrocarbon chain also increases which makes it difficult for water molecules to interact with carboxylic molecules. Dispersion forces turn out to be more predominant than dipole forces. Hence, the solubility of carboxylic acids decreases on increasing n.