Acid Base Concepts And Principles

Step 1: Understanding the Concept:
Solubility in aqueous depends on the acidity of the compound. is a strong base; therefore, compounds that are significantly more acidic than water (such as phenols, carboxylic acids, and sulfonic acids) will react with to form water-soluble salts.

Step 2: Key Formula or Approach:
1. Identify the functional groups: Carboxylic acids ( ), Phenols ( on benzene), and Sulfonic acids ( ) are typically soluble. 2. Alcohols ( on alkyl chains) and simple amines are generally not acidic enough to react with .

Step 3: Detailed Explanation:
1. In a standard set for this question (usually containing Phenol, Benzoic acid, o-Cresol, and -Nitrophenol), these four would react with . 2. Phenol forms Sodium Phenoxide ( ). 3. Benzoic acid forms Sodium Benzoate ( ). 4. -Nitrophenol is even more acidic than phenol due to the electron-withdrawing nitro group and dissolves readily. 5. If the list includes alcohols like Benzyl alcohol or Cyclohexanol, they will remain insoluble as they do not form stable salts with .

Step 4: Final Answer:
The total number of soluble compounds is 4.

Step 1: Understanding the Concept:
Acidity depends on the stability of the conjugate base formed after losing a proton. Carboxylic acids are generally much stronger acids than phenols because the carboxylate ion is more resonance-stabilized than the phenoxide ion. Electron-withdrawing groups (EWG) increase acidity, while electron-donating groups (EDG) decrease it.

Step 3: Detailed Explanation:
1. Carboxylic acids vs Phenols: Benzoic acids (D, E) are more acidic than phenols (A, B, C).
2. Within benzoic acids: p-nitrobenzoic acid (D) has a strong EWG ( and effect of ), making it stronger than benzoic acid (E). So, .
3. Within phenols: p-nitrophenol (B) has a strong EWG ( ), making it stronger than phenol (A). p-methoxyphenol (C) has a strong EDG ( effect of ), making it the weakest. So, .
Combining the sequences: .

Step 4: Final Answer:
The descending order of acidity is D > E > B > A > C.