[VISUAL] The Lewis electron-dot diagrams of the HClO3 molecule and the HClO2 molecule are shown abov — Acids and Bases Chemistry Question

STEPS:

1. Understand what determines acid strength in oxoacids: The strength of an oxoacid is determined by how easily the acidic hydrogen ion ($\text{H}^+$) can be donated. This is governed by two key factors: the polarity of the polar covalent $\text{O}-\text{H}$ bond (making it easier to break) and the stability of the resulting conjugate base after deprotonation.
2. Compare the chemical formulas and structures of the two acids: The two acids under comparison are chloric acid ($\text{HClO}_3$) and chlorous acid ($\text{HClO}_2$). Their corresponding conjugate bases are the chlorate anion ($\text{ClO}_3^-$) and the chlorite anion ($\text{ClO}_2^-$), respectively.
3. Analyze the role of additional electronegative oxygen atoms: Oxygen is a highly electronegative element. In $\text{HClO}_3$, there is an additional electronegative oxygen atom bonded to the central chlorine atom compared to $\text{HClO}_2$.
4. Evaluate the inductive effect and charge delocalization:
* This additional oxygen atom pulls electron density away from the central chlorine atom and the $\text{O}-\text{H}$ bond via the inductive effect, which highly polarizes the $\text{O}-\text{H}$ bond and makes the proton much easier to release.
* Furthermore, when the acid dissociates, the negative charge on the resulting conjugate base ($\text{ClO}_3^-$) can be delocalized (spread out) over a larger number of highly electronegative oxygen atoms. Delocalizing the negative charge increases the thermodynamic stability of the conjugate base.
5. Conclude which acid is stronger: Because a more stable conjugate base corresponds to a stronger parent acid, $\text{HClO}_3$ is the stronger acid because the additional electronegative oxygen atom stabilizes the conjugate base, confirming Option B.

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WHY_OTHERS_WRONG:

• Option A is incorrect: While it correctly identifies $\text{HClO}_3$ as the stronger acid, it incorrectly attributes this strength to London dispersion forces. London dispersion forces are weak *intermolecular* attractions between separate molecules that govern physical properties like boiling point; they play no role in the chemical process of covalent bond cleavage during acid dissociation.
• Option C is incorrect: This option incorrectly identifies $\text{HClO}_2$ as the stronger acid and further makes the chemically irrelevant claim about London dispersion forces.
• Option D is incorrect: This option incorrectly identifies $\text{HClO}_2$ as the stronger acid. Additionally, the lone pairs on the chlorine atom do not stabilize the conjugate base; rather, having more lone pairs on the central atom concentrates localized negative charge, which makes the conjugate base more reactive (a stronger conjugate base, meaning a weaker parent acid).