Question

What is meant by a strong acid? Are the strong acids also strong electrolytes? Explain.

Short answer

A strong acid is an acid that completely dissociates in water, releasing all of its hydrogen ions (H+) and forming hydronium ions (H3O+) and corresponding anions. This results in a high concentration of ions and low pH value. Examples include hydrochloric acid (HCl), nitric acid (HNO3), and sulfuric acid (H2SO4). Strong acids are also considered strong electrolytes, as their complete dissociation in water produces a high concentration of ions, allowing the solution to conduct electricity efficiently.

Step-by-step solution

Definition of a Strong Acid

A strong acid is an acid that completely dissociates in water, releasing all of its hydrogen ions (H+). This means that the acid fully reacts with the water to form hydronium ions (H3O+) and the corresponding anion. Because of this complete dissociation, strong acids have a high concentration of ions, which results in a low pH value.

Examples of Strong Acids

Some examples of strong acids include: 1. Hydrochloric acid (HCl) 2. Nitric acid (HNO3) 3. Sulfuric acid (H2SO4) 4. Perchloric acid (HClO4) 5. Hydrobromic acid (HBr) 6. Hydroiodic acid (HI)

Relation of Strong Acids to Strong Electrolytes

A strong electrolyte is a substance that completely dissociates in water, producing a high concentration of ions that can freely move and conduct electricity. Since strong acids completely dissociate in water and release a high concentration of ions, they are also considered strong electrolytes. For example, when hydrochloric acid (HCl) is dissolved in water, it dissociates completely into H+ and Cl- ions: \[ HCl_{(aq)} -> H^+_{(aq)} + Cl^-_{(aq)} \] Because all of the HCl molecules dissociate into ions, the solution has a high concentration of ions (H+ and Cl-), which makes it a strong electrolyte.

Conclusion

In conclusion, a strong acid is an acid that completely dissociates in water, producing a high concentration of hydrogen ions. Strong acids are also considered strong electrolytes because of their complete dissociation in water and their resulting high concentration of ions, allowing the solution to conduct electricity efficiently.

Key concepts

Electrolytes

To understand the role of strong acids as electrolytes, it is important to grasp what electrolytes are. Electrolytes are substances that, when dissolved in water, split into ions. These ions can move freely in the solution, allowing it to conduct electricity.

Strong acids are classified as strong electrolytes because they fully dissociate into ions when mixed with water. This complete dissociation provides a high concentration of ions, making the solution highly conductive.

• Substances like salts, certain acids, and bases can act as electrolytes.
• The capability of a solution to conduct electricity depends on the concentration and mobility of ions in the solution.

In summary, when strong acids dissolve in water, they not only release hydrogen ions but also anions, which result in effective electrical conductivity.

Chemical Dissociation

Chemical dissociation refers to the breaking down of a compound into its constituent ions. In the context of strong acids, dissociation is key to their definition and behavior in solutions. When strong acids are added to water, they split entirely into hydrogen ions (H+) and corresponding anions.

This complete dissociation is what characterizes an acid as strong. For example, hydrochloric acid (HCl) will fully separate into H+ and Cl- ions when in water.

• Chemical dissociation for strong acids is a straightforward, irreversible process.
• 100% dissociation means more free ions in the solution, which contributes to the acid's low pH level.

The extent of chemical dissociation sets strong acids apart from weak acids, which do not dissociate completely.

Hydronium Ions

Hydronium ions \( H_3O^+ \) are a result of the interaction between hydrogen ions (H+) released from the acid and water molecules. Whenever a strong acid dissociates in water, the hydrogen ions combine with water molecules to form hydronium ions.

The reaction can be represented as:

• \( H^+ + H_2O ightarrow H_3O^+ \)

The formation of hydronium ions is crucial because it determines the acidic nature of the solution. The more complete the dissociation, the greater the concentration of hydronium ions, which effectively reduces the pH value of the solution.

Strong acids, by virtue of their full dissociation, lead to an increased presence of hydronium ions, culminating in a pronounced acidic character.

pH Value

The pH value is a measure that indicates the acidity or alkalinity of a solution. It is based on the concentration of hydronium ions \( H_3O^+ \) in the solution. Strong acids contribute to a low pH level due to their high concentration of hydronium ions.

The pH scale ranges from 0 to 14, where:

• Acidic solutions have a pH less than 7.
• Neutral solutions have a pH of 7.
• Basic solutions have a pH greater than 7.

When it comes to strong acids, their high level of dissociation results in more hydronium ions, leading to a pH value closer to zero. Consequently, understanding strong acids involves recognizing how they affect the pH value of a solution due to their chemical nature.