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Ch.16 - Acids and Bases
Chapter 16, Problem 45a,b

Pick the stronger base from each pair. a. F or Cl b. NO2 or NO3

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Identify the periodic trend for halides: Fluoride (F) and Chloride (Cl) are both halide ions. In general, the basicity of halide ions decreases as you move down the group in the periodic table.
Compare the electronegativity: Fluoride is more electronegative than Chloride, which means it holds onto its electrons more tightly and is less willing to donate them, making it a weaker base.
Determine the conjugate acid strength: The strength of a base is inversely related to the strength of its conjugate acid. HF is a weaker acid than HCl, so F is a stronger base than Cl.
Analyze the resonance stabilization: For NO2 and NO3, consider the resonance structures. NO3 has more resonance structures, which stabilizes the ion and makes it a weaker base.
Evaluate the conjugate acid strength for nitrites and nitrates: HNO3 is a stronger acid than HNO2, indicating that NO2 is a stronger base than NO3.

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Key Concepts

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

Acid-Base Theory

Acid-base theory explains the behavior of acids and bases in chemical reactions. According to the Brønsted-Lowry theory, an acid is a proton donor, while a base is a proton acceptor. The strength of a base is determined by its ability to accept protons, which is influenced by the stability of the resulting conjugate acid.
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Conjugate Acid-Base Pairs

Conjugate acid-base pairs consist of two species that differ by the presence of a proton. When a base accepts a proton, it forms its conjugate acid, and the strength of the base can be inferred from the stability of its conjugate acid. A weaker conjugate acid indicates a stronger base, as it is less likely to donate a proton back.
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Electronegativity and Basicity

Electronegativity is the tendency of an atom to attract electrons in a bond. In the context of basicity, a more electronegative atom will hold onto its electrons more tightly, making it less likely to accept protons. Therefore, when comparing bases, the one with the less electronegative atom is typically the stronger base, as it can more readily accept protons.
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