Which of the following is the strongest acid? (a) \(\mathrm{ClO}_{3}(\mathrm{OH})\) (b) \(\mathrm{ClO}_{2}(\mathrm{OH})\) (c) \(\mathrm{SO}(\mathrm{OH})_{2}\) (d) \(\mathrm{SO}_{2}(\mathrm{OH})_{2}\)

In the context of acid strength, conjugate base stability plays a pivotal role. A conjugate base is what remains of an acid after it donates a proton. The key to understanding this concept is recognizing that the more stable the conjugate base, the stronger its corresponding acid will be. This stability is often gauged by the base's ability to distribute and accommodate the negative charge left behind after the acid loses a proton.

Factors Influencing Stability

Several factors determine the stability of a conjugate base, including the electronegativity of atoms near the negative charge, the presence of resonance structures, and the inductive effect of substituent groups. By examining which bases are adept at dispersing the negative charge, we can predict the relative strength of their parent acids. In the example of oxyacids, the conjugate base with more oxygen atoms has more opportunities to delocalize the negative charge through resonance, which typically leads to increased stability and, hence, a stronger acid.

Electronegativity is a fundamental concept when discussing acid strength. Defined as an atom's tendency to attract electrons within a bond, electronegativity directly impacts the stability of the conjugate base. Atoms with higher electronegativity pull electron density closer, which can help stabilize additional negative charges in the conjugate base.

Electronegativity in Acid Comparison

When comparing acids, the more electronegative the atom bonded to the acidic hydrogen, the stronger the acid. In the given exercise, chlorine is more electronegative than sulfur, which suggests that acids with chlorine as the central atom are generally stronger than those with sulfur, given comparable structures.

Resonance stabilization is another crucial factor affecting acid strength. Resonance occurs when the electron distribution within a molecule can be represented by two or more valid Lewis structures. These structures, called resonance structures, delocalize negative charges over several atoms, reducing the electron density on any single atom and thus stabilizing the conjugate base.

Resonance and Acidity

Acids whose conjugate bases have resonance stabilization are typically stronger because the spread-out charge is less repulsive, making it easier for the base to exist without reverting to its acid form. In the exercise, when analyzing which conjugate base is most stabilized by resonance, the central atom connected to multiple highly electronegative oxygens will likely provide the most resonance stabilization, leading to a strong acid.

The inductive effect refers to the influence of polar bonds on the distribution of electrons in a molecule. It has a considerable impact on acid strength, particularly in molecules where electronegative elements are present.

Understanding Inductive Effects

Electronegative atoms can pull electron density toward themselves through sigma bonds. This withdrawal of electron density can help stabilize the negative charge on a conjugate base, effectively increasing the parent acid's strength. In our exercise, oxyacids with more oxygen atoms bonded to the central atom would exhibit a stronger inductive effect, leading to increased acid strength.

Focusing on oxyacids, their strength is largely determined by the number of oxygen atoms bonded to the central atom. Oxygen's high electronegativity and its ability to participate in resonance stabilization make it a key player in this determination.

Oxyacids and Their Strength

Generally, the more oxygen atoms present, the more strongly the negative charge is delocalized over the molecule, resulting in a stronger acid. The exercise addresses oxyacids, and we can see that \(\mathrm{ClO}_{3}(\mathrm{OH})\) with three oxygens likely represents the strongest acid because it can spread its charge most efficiently across multiple electronegative oxygen atoms.

When comparing acid strengths, it's essential to consider several factors: the stability of the conjugate base, resonance structures, the central atom's electronegativity, and the inductive effect. By systematically evaluating each of these aspects, we can determine the strongest acid among a given set.

Applying Concepts to Compare Acids

Returning to the exercise, by looking at each molecule's structure and accounting for the number of oxygen atoms, the electronegativity of the central atom, and the potential for resonance stabilization, it becomes clear why \(\mathrm{ClO}_{3}(\mathrm{OH})\) is assessed to be the strongest acid of the options provided. Its conjugate base is the most stable considering all discussed factors, leading to the conclusion that its parent acid is the strongest.