Textbook Question
Chlorine reacts with molten sulfur to yield disulfur dichloride, a yellowish-red liquid. Propose a structure for disulfur dichloride.
Ch.22 - The Main Group Elements
Chapter 22, Problem 155
Explain why acid strength increases in the order HIO < HBrO < HClO.
Verified step by step guidance1
Step 1: Understand that acid strength is influenced by the stability of the conjugate base formed after the acid donates a proton (H+). A more stable conjugate base corresponds to a stronger acid.
Step 2: Recognize that the stability of the conjugate base is affected by the electronegativity of the central atom. More electronegative atoms can better stabilize the negative charge on the conjugate base.
Step 3: Compare the electronegativities of the central atoms: Iodine (I), Bromine (Br), and Chlorine (Cl). Chlorine is the most electronegative, followed by Bromine, and then Iodine.
Step 4: Relate the electronegativity to acid strength: Since Cl is more electronegative than Br and I, the conjugate base ClO- is more stable than BrO- and IO-, making HClO the strongest acid.
Step 5: Conclude that the order of increasing acid strength is HIO < HBrO < HClO due to the increasing electronegativity of the central atom, which stabilizes the conjugate base more effectively.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acid Strength
Acid strength refers to the ability of an acid to donate protons (H+) in a solution. Stronger acids dissociate more completely in water, leading to a higher concentration of H+ ions. The strength of an acid is influenced by the stability of its conjugate base; a more stable conjugate base corresponds to a stronger acid.
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Binary Acid Strengths
Conjugate Base Stability
The stability of a conjugate base is crucial in determining acid strength. When an acid donates a proton, the remaining species is the conjugate base. Factors such as electronegativity and the size of the atom to which the negative charge is assigned affect this stability. A more stable conjugate base results in a stronger acid.
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Electronegativity and Bond Strength
Electronegativity is the tendency of an atom to attract electrons. In oxyacids like HIO, HBrO, and HClO, the electronegativity of the central atom (I, Br, Cl) affects the bond strength between the hydrogen and the central atom. As electronegativity increases, the bond becomes weaker, making it easier for the acid to release H+, thus increasing acid strength.
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