Identify the stronger base in each of the following pairs.
Explain your reasoning.
(c) HS^- or OH^-

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Identify the conjugate acids of each base: HS^- is the conjugate base of H2S, and OH^- is the conjugate base of H2O.

Recall that the strength of a base is inversely related to the strength of its conjugate acid.

Compare the acid strengths: H2S is a stronger acid than H2O.

Since H2S is a stronger acid, its conjugate base (HS^-) is weaker than the conjugate base of the weaker acid (OH^-).

Conclude that OH^- is the stronger base compared to HS^-.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Brønsted-Lowry Acids and Bases

The Brønsted-Lowry theory defines acids as proton donors and bases as proton acceptors. In this context, a stronger base is one that can more readily accept protons. Understanding this concept is crucial for comparing the basicity of different species, such as HS⁻ and OH⁻.

Conjugate Acid-Base Pairs

Conjugate acid-base pairs consist of an acid and its corresponding base that differ by a single proton. For example, HS⁻ is the conjugate base of H₂S, while OH⁻ is the conjugate base of H₂O. Analyzing these pairs helps in determining the relative strength of bases based on their ability to form stable conjugate acids.

Electronegativity and Basicity

Electronegativity refers to the tendency of an atom to attract electrons. In the context of basicity, a less electronegative atom is generally better at donating electron density to bond with protons. Comparing the electronegativities of sulfur in HS⁻ and oxygen in OH⁻ can provide insight into which species is a stronger base.

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