15.2 Lewis Acids and Bases

15.2 Lewis Acids and Bases

  • The first thing you should notice is that the solution you are looking at has a dissolved metal in it.
  • We can use the formula, but we can also make an assumption to make the calculation simpler.
  • The Lewis model of acid-base chemistry was proposed in 1923.
  • A coordinate covalent bond occurs when a water molecule combines with a hydrogen ion.
    • A coordinate covalent bond results when an ammonia molecule and a hydrogen ion form an ammonia ion.
    • The equations are shown here.
  • A Lewis acid-base reaction occurs when a base donates electrons to an acid.
    • The general application of the Lewis concept is shown in the following equations.
  • There are only six electrons in the valence shell of the boron atom.
  • The reaction of a acid with a base fits into the Lewis concept.
    • According to the Lewis concept, an acid-base adduct such as HCl is an acid-base adduct.
    • The definitions of acids and bases in the two theories are quite different.
  • When the concentration of the metal ion in solution is decreased through the formation of complex (polyatomic) ion in a Lewis acid-base reaction, many ionic particles are dissolved.
  • The neutral molecule H2O or NH3 can be one of the ligands.
    • Lewis bases can be donated by the ligands, donating a pair of electrons to the central atom.
    • A transitional metal ion is created when the ligands aggregate themselves around the central atom.
    • The complex ion formed in these reactions can't be predicted.
    • The types of bonds formed in complex ion are called coordinate covalent bonds.
    • Complex ion are sometimes referred to as coordination complexes.
    • In upcoming chapters, this will be studied further.
  • In the exercises for this section, we will work with dissociation constants.
    • Table 15.2 is a table of formation constants.

When we add ammonia to a mixture of silver chloride and water, what happens?

  • Ag(NH3)2 is formed by 3.
  • There is more silver chloride.
    • All of the silver chloride can be dissolved if the concentration of ammonia is high.
  • Determine the direction of change.
  • The reaction shifts to the left to reach equilibrium because it is infinitely large.