Question

Explain why salts can be acidic, basic, or neutral, and show examples. Do this without specific numbers.

Short answer

Salts can be acidic, basic, or neutral depending on the properties of their parent acid and base. Neutral salts, such as sodium chloride (NaCl), are formed from the reaction between a strong acid and a strong base, and they do not affect the pH of the solution. Acidic salts, like ammonium chloride (NH4Cl), result from the reaction between a strong acid and a weak base, creating a solution with a pH less than 7. Basic salts, such as sodium acetate (NaCH3COO), are formed from the reaction between a weak acid and a strong base, resulting in a solution with a pH greater than 7.

Step-by-step solution

Understanding Acids and Bases

Before we discuss about salts, let's briefly understand what acids and bases are. Acids are substances that can donate hydrogen ions (H+), whereas bases are substances that can accept or donate hydroxide ions (OH-). In water, this combines to form hydronium ions (H3O+) and hydroxide ions (OH-). When an acid and a base react, they form a salt and water in a process called a neutralization reaction.

Formation of Salts

Salts are formed by the reaction between an acid and a base. They usually result from the cation from the base (usually a metal) and the anion from the acid. In this reaction, we can observe the transfer of hydrogen ions (H+) and hydroxide ions (OH-). The acid-base properties of salts can sometimes reflect the properties of their parent acid and base.

Neutral Salts

Neutral salts are formed when a strong acid reacts with a strong base. Both the acid and the base completely dissociate in the solution, resulting in equal amounts of H3O+ and OH- ions, which gives a pH of 7. The salt in this case doesn't affect the pH of the solution. Example: Sodium chloride (NaCl) - formed from the reaction between the strong acid hydrochloric acid (HCl) and the strong base sodium hydroxide (NaOH).

Acidic Salts

Acidic salts are formed when a strong acid reacts with a weak base. In this case, the resulting salt has a cation (from the base) that does not react with water, and an anion (from the acid) that can accept water molecules and generate H3O+ ions. This results in a solution with a pH less than 7. Example: Ammonium chloride (NH4Cl) - formed from the reaction between the strong acid hydrochloric acid (HCl) and the weak base ammonia (NH3).

Basic Salts

Basic salts are formed when a weak acid reacts with a strong base. The cation (from the base) is able to react with water molecules generating OH- ions, while the anion (from the acid) remains unreactive. The pH of the solution containing a basic salt is greater than 7. Example: Sodium acetate (NaCH3COO) - formed from the reaction between the weak acid acetic acid (CH3COOH) and the strong base sodium hydroxide (NaOH). In conclusion, salts can be acidic, basic, or neutral, depending on the nature of the parent acid and base from which they are formed. Neutral salts come from the reaction between a strong acid and a strong base, acidic salts come from the reaction between a strong acid and a weak base, and basic salts come from the reaction between a weak acid and a strong base.