Problem 62 - Chemistry Matter and Change

Question

Use the symbols \(<,>,\) and \(=\) to express the relationship between the concentrations of \(\mathrm{H}^{+}\) ions and \(\mathrm{OH}^{-}\) ions in acidic, neutral, and basic solutions.

Step-by-Step Solution

Answer

In acidic, neutral, and basic solutions, the relationship between the concentrations of \(\mathrm{H}^{+}\) ions and \(\mathrm{OH}^{-}\) ions can be expressed as follows: - Acidic solution: \(\mathrm{[H^{+}] > [OH^{-}]}\) - Neutral solution: \(\mathrm{[H^{+}] = [OH^{-}]}\) - Basic solution: \(\mathrm{[H^{+}] < [OH^{-}]}\)

Step 1: Understand the definitions of acidic, neutral, and basic solutions

In order to express the relationship between the concentrations of \(\mathrm{H}^{+}\) and \(\mathrm{OH}^{-}\) ions in different solutions, we need to know the definitions of acidic, neutral, and basic solutions: - Acidic solution: A solution with a higher concentration of \(\mathrm{H}^{+}\) ions than \(\mathrm{OH}^{-}\) ions. - Neutral solution: A solution with equal concentrations of \(\mathrm{H}^{+}\) and \(\mathrm{OH}^{-}\) ions. - Basic solution: A solution with a lower concentration of \(\mathrm{H}^{+}\) ions than \(\mathrm{OH}^{-}\) ions.

Step 2: Apply the definitions to express the relationships

We will now use the symbols \(<\), \(>\), and \(=\) to show the relationship between the concentrations of \(\mathrm{H}^{+}\) ions and \(\mathrm{OH}^{-}\) ions in each type of solution: - Acidic solution: The concentration of \(\mathrm{H}^{+}\) ions is greater than the concentration of \(\mathrm{OH}^{-}\) ions, which can be written as: \[\mathrm{[H^{+}] > [OH^{-}]}\] - Neutral solution: The concentration of \(\mathrm{H}^{+}\) ions is equal to the concentration of \(\mathrm{OH}^{-}\) ions, which can be written as: \[\mathrm{[H^{+}] = [OH^{-}]}\] - Basic solution: The concentration of \(\mathrm{H}^{+}\) ions is less than the concentration of \(\mathrm{OH}^{-}\) ions, which can be written as: \[\mathrm{[H^{+}] < [OH^{-}]}\] To sum up, the relationship between the concentrations of \(\mathrm{H}^{+}\) ions and \(\mathrm{OH}^{-}\) ions in acidic, neutral, and basic solutions can be expressed using the following symbols: - Acidic solution: \(\mathrm{[H^{+}] > [OH^{-}]}\) - Neutral solution: \(\mathrm{[H^{+}] = [OH^{-}]}\) - Basic solution: \(\mathrm{[H^{+}] < [OH^{-}]}\)

Key Concepts

Acidic Solution

An acidic solution is a type of chemical solution that is characterized by having a higher concentration of hydrogen ions (\(\mathrm{H}^{+}\)) compared to hydroxide ions (\(\mathrm{OH}^{-}\)).
This can be mathematically represented by the equation \([\mathrm{H}^{+}] > [\mathrm{OH}^{-}]\). The pH scale, which measures how acidic or basic a solution is, ranges from 0 to 14, where 7 is neutral. Acidic solutions have a pH less than 7.
As the concentration of \(\mathrm{H}^{+}\) ions increases, the pH value decreases, indicating a stronger acidity.Some common examples of acidic solutions include:

• Lemon juice, which contains citric acid.
• Vinegar, which contains acetic acid.
• Stomach acid, primarily composed of hydrochloric acid (HCl).

Understanding acidic solutions involves recognizing how these solutions interact with other substances.
For instance, they typically react with metals, bases, and carbonates, often producing gas and heat.
Knowing the properties of acidic solutions is crucial in fields like chemistry, biology, and environmental science.

Neutral Solution

Neutral solutions are unique in that they have a balance between the concentration of hydrogen ions (\(\mathrm{H}^{+}\)) and hydroxide ions (\(\mathrm{OH}^{-}\)).
This balance is mathematically expressed as \([\mathrm{H}^{+}] = [\mathrm{OH}^{-}]\).In terms of the pH scale, a neutral solution has a pH value of exactly 7. This is the central point of the scale, indicating an equal presence of \(\mathrm{H}^{+}\) and \(\mathrm{OH}^{-}\) ions.
An example of a neutral solution is pure water, where the concentration of these ions are perfectly balanced.It is important to understand how neutral solutions react with acids and bases:

• When mixed with an acid, the pH of a neutral solution will decrease, becoming more acidic.
• Conversely, when mixed with a base, the pH will increase, becoming more basic.

Neutral solutions play a significant role in many natural and industrial processes.
For example, they are essential for maintaining the proper pH in biological systems and can be used to dilute acids or bases in laboratory settings.
Mastery of the concept of neutrality is important in subjects like chemistry, physiology, and environmental science.

Basic Solution

Basic solutions, also known as alkaline solutions, are characterized by a higher concentration of hydroxide ions (\(\mathrm{OH}^{-}\)) than hydrogen ions (\(\mathrm{H}^{+}\)).
This relationship can be expressed using the equation \([\mathrm{H}^{+}] < [\mathrm{OH}^{-}]\).On the pH scale, basic solutions have a pH greater than 7. The higher the pH, the more basic the solution.
As the concentration of \(\mathrm{OH}^{-}\) ions increases, the solution becomes more alkaline.Some everyday examples of basic solutions include:

• Baking soda solution, which is commonly used for cleaning.
• Household ammonia, often used in detergents and cleaners.
• Sea water, which is naturally alkaline.

Understanding basic solutions is critical because they can have strong reactions, especially with acidic solutions.
These reactions are important for various chemical processes and can be used to neutralize acidic environments.
Studying basic solutions is essential in fields such as chemistry, medicine, and environmental studies.