Problem 8 The acids in Table 2 are divided... [FREE SOLUTION]

Chapter 43: Problem 8

The acids in Table 2 are divided into two groups: those with \(K_{\mathrm{a}}>1\) and those with \(\mathrm{K}_{\mathrm{a}}<1\). Describe each of these two groups in terms of percent dissociation.

Short Answer

Expert verified

Acids with a Ka greater than 1 are strong acids and dissociate almost completely in solution, leading to a percent dissociation near 100%. In contrast, acids with a Ka less than 1 are weak acids and dissociate to a lesser extent, resulting in a lower percent dissociation.

Step by step solution

Understand Ka and Percent Dissociation

The acid dissociation constant, Ka, is a measure of the strength of an acid in solution. Larger Ka values correspond to stronger acids. Percent dissociation is a measure of the degree to which the acid molecules separate or dissociate into their ions in solution. The higher the percent dissociation, the more the acid has dissociated into its ions.

Describe Acids with Ka > 1

Acids with Ka greater than 1 are strong acids. This means that they dissociate almost completely in solution. Therefore, these types of acids have a percent dissociation that approaches 100%.

Describe Acids with Ka < 1

On the other hand, acids with Ka less than 1 are weak acids. They dissociate to a lesser extent in solution, thus, they have a percent dissociation much less than 100%.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Percent Dissociation

Percent dissociation is an important concept when studying acids as it tells us how much of an acid dissociates into ions in a solution. The formula to calculate percent dissociation is:

Percent Dissociation = \( \frac{[ ext{ionized acid}]}{[ ext{initial acid}]} \times 100\% \)

This measure is crucial as it indicates the extent to which an acid releases its hydrogen ions (H鈦�) into the solution. A high percent dissociation means most of the acid molecules are split into ions, implying the acid is likely strong. Conversely, a low percent dissociation suggests fewer molecules are ionized, indicating a weak acid. Understanding this helps in identifying how an acid will behave in different chemical reactions.

Strong Acids

Strong acids are a group of acids that completely dissociate in aqueous solutions. They have a high acid dissociation constant (\(K_{\text{a}} > 1\)). This high value reflects their complete ionization in water. Because of their full dissociation, strong acids have a percent dissociation close to 100%. That means almost all acid molecules split into ions.Common Characteristics of Strong Acids:

Typically have higher electrical conductivity due to more free ions.
React vigorously with bases and metals, often producing hydrogen gas.
Examples include hydrochloric acid (HCl) and sulfuric acid (H鈧係O鈧�).

Their predictable behavior in reactions makes them vital for industrial and laboratory use.

Weak Acids

In contrast, weak acids are acids that do not completely dissociate in solution. Their acid dissociation constants (\(K_{\text{a}} < 1\)) indicate partial ionization only.These acids have a much lower percent dissociation often far less than 100%. It's important to note that many organic acids fall into this category, such as acetic acid found in vinegar.Attributes of Weak Acids:

They tend to be less corrosive and have milder tastes compared to strong acids.
Possess lower electrical conductivity due to fewer ions present.
Weak acids often act as buffering agents, resisting pH change when small amounts of acid or base are added.

Weak acids are essential in biological systems, ensuring processes occur at specific pH levels.

Acid Strength

Acid strength refers to an acid's ability to donate protons (H鈦� ions) in a solution. It is directly linked to the acid dissociation constant, \(K_{\text{a}}\), which quantifies this ability.High \(K_{\text{a}}\) values denote strong acids as they are efficient in donating protons. Lower \(K_{\text{a}}\) values are typical of weak acids that partially dissociate.Factors Affecting Acid Strength:

Electronegativity: Strong acids typically have more electronegative atoms pulling electrons away, enhancing ionization.
Atom Size: Larger atom sizes often lead to weaker bonds and easier ionization, boosting acid strength.
Resonance: Delocalization of charge through resonance can stabilize ions, making acids stronger.

Understanding these properties allows chemists to predict reaction outcomes effectively and formulate products for specific purposes.

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91影视

The acids in Table 2 are divided into two groups: those with \(K_{\mathrm{a}}>1\) and those with \(\mathrm{K}_{\mathrm{a}}<1\). Describe each of these two groups in terms of percent dissociation.

Short Answer

Step by step solution

Understand Ka and Percent Dissociation

Describe Acids with Ka > 1

Describe Acids with Ka < 1

Key Concepts

Percent Dissociation

Strong Acids

Weak Acids

Acid Strength

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