Question

Which of the following acids are classified as strong acids? a. \(\mathrm{HNO}_{3}\) b. \(\mathrm{CH}_{3} \mathrm{COOH}\left(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)\) c.\( HCl\) d. \(HF\) e. \(\mathrm{HClO}_{4}\)

Short answer

The strong acids among the given options are: a. \(\mathrm{HNO}_{3}\), c. \(HCl\), and e. \(\mathrm{HClO}_{4}\).

Step-by-step solution

Identify the strong acids

We have six classic strong acids: \(\mathrm{HCl}\), \(\mathrm{HBr}\), \(\mathrm{HI}\), \(\mathrm{HNO}_{3}\), \(\mathrm{HClO}_{4}\), and \(\mathrm{H}_{2}\mathrm{SO}_{4}\). We will now compare these with the given acids to decide whether they are strong acids or not.

Analyze the given acids

Let's go through each given acid and see if it is one of the classic strong acids: a. \(\mathrm{HNO}_{3}\) (nitric acid) is on the list of classic strong acids. b. \(\mathrm{CH}_{3} \mathrm{COOH}\left(\mathrm{HC}_{2} \mathrm{H}_{3}\mathrm{O}_{2}\right)\) is acetic acid, which is a weak acid. c. \(HCl\) (hydrochloric acid) is on the list of classic strong acids. d. \(HF\) (hydrofluoric acid) is a weak acid. e. \(\mathrm{HClO}_{4}\) (perchloric acid) is on the list of classic strong acids.

State the strong acids

By comparing the given acids with the classic strong acids, we have determined that the strong acids among the given options are: a. \(\mathrm{HNO}_{3}\) c. \(HCl\) e. \(\mathrm{HClO}_{4}\)

Key concepts

Acid Classification

Acid classification is a method used to categorize acids based on their strength and dissociation behavior in water. Generally, there are two main types of acids: strong acids and weak acids. This classification helps understand their chemical nature and behavior in various reactions.

• **Strong Acids**: These acids ionize completely in water, meaning they dissociate into their ions to a large extent. This results in a high concentration of hydrogen ions (or protons) in solution, making them very effective in reactions.
• **Weak Acids**: In contrast, weak acids do not ionize completely. They only partially dissociate, leading to a lower concentration of hydrogen ions in solution.

By understanding which acids are classified as strong or weak, we can predict their behavior in scientific experiments and industrial processes.

List of Strong Acids

There are several well-known strong acids that are often referenced in chemistry:

• **Hydrochloric Acid ( HCl )**: Commonly used in laboratory and industrial settings.
• **Hydrobromic Acid ( HBr )**: Similar to hydrochloric acid in terms of strength and uses.
• **Hydroiodic Acid ( HI )**: Known for being one of the strongest acids available.
• **Nitric Acid ( HNO_3 )**: Used in fertilizers and explosives.
• **Perchloric Acid ( HClO_4 )**: Often used in analytical chemistry due to its high strength.
• **Sulfuric Acid ( H_2SO_4 )**: Widely used in industry, particularly in the production of fertilizers and chemical manufacturing.

Knowing this list helps determine which acids will fully dissociate in water, making them suitable for specific chemical reactions.

Weak Acids versus Strong Acids

Understanding the differences between weak acids and strong acids is key in predicting their behavior in various chemical contexts. Weak acids only partially dissociate in water, meaning fewer hydrogen ions are released. This makes their solutions less acidic compared to strong acids. Common examples of weak acids include acetic acid ( CH_3COOH ) and hydrofluoric acid ( HF ). In contrast, strong acids dissociate completely, or nearly so, in solution, resulting in a higher concentration of hydrogen ions. This makes them much stronger in terms of acidity and more reactive in chemical processes. Some key differences between weak and strong acids include:

• **Degree of Ionization**: Strong acids fully ionize in solution, while weak acids do not.
• **pH Levels**: Solutions of strong acids have a lower pH than those of weak acids of the same concentration.
• **Electrical Conductivity**: Strong acids make better conductors of electricity in solution due to the higher ion concentration.

These properties significantly impact how acids are used in practical and theoretical chemistry.