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Engineering LibreTexts

7.1: Acid/Base Chemistry

  • Page ID
    31559
    • 7.1.1: pH and pOH
      The concentration of hydronium ion in a solution of an acid in water is greater than 1.0×10−7M1.0×10−7M 1.0 \times 10^{-7}\; M at 25 °C. The concentration of hydroxide ion in a solution of a base in water is greater than 1.0×10−7M1.0×10−7M 1.0 \times 10^{-7}\; M at 25 °C. The concentration of H3O+ in a solution can be expressed as the pH of the solution; pH=−logH3O+pH=−log⁡H3O+\ce{pH} = -\log \ce{H3O+}. The concentration of OH− can be expressed as the pOH of the solution: pOH=−log[OH−]pOH=−log⁡[
    • 7.1.2: Relative Strengths of Acids and Bases
      The strengths of Brønsted-Lowry acids and bases in aqueous solutions can be determined by their acid or base ionization constants. Stronger acids form weaker conjugate bases, and weaker acids form stronger conjugate bases. Thus strong acids are completely ionized in aqueous solution because their conjugate bases are weaker bases than water. Weak acids are only partially ionized because their conjugate bases are compete successfully with water for possession of protons.
    • 7.1.3: Polyprotic Acids
      An acid that contains more than one ionizable proton is a polyprotic acid. The protons of these acids ionize in steps. The differences in the acid ionization constants for the successive ionizations of the protons in a polyprotic acid usually vary by roughly five orders of magnitude. As long as the difference between the successive values of Ka of the acid is greater than about a factor of 20, it is appropriate to break down the calculations of the concentrations sequentially.
    • 7.1.4: Coupled Equilibria
      Several systems we encounter consist of multiple equilibria, systems where two or more equilibria processes are occurring simultaneously. Some common examples include acid rain, fluoridation, and dissolution of carbon dioxide in sea water. When looking at these systems, we need to consider each equilibrium separately and then combine the individual equilibrium constants into one solubility product or reaction quotient expression using the tools from the first equilibrium chapter.