14.4 Hydrolysis of Salt Solutions

14.4 Hydrolysis of Salt Solutions

  • When an acid and base are mixed, they undergo a neutralization reaction.
    • A neutral solution of an acid and a base seems to be implied by the word neutralization.
    • This is sometimes true, but the salts that are formed in these reactions may have acidic or basic properties of their own.
  • When there are equal concentrations of hydronium and hydroxide ion, the solution is neutral.
    • An acid-base neutralization reaction occurs when we mix solutions of acid and base.
    • We may find that the solution is not neutral even if we mix equivalent quantities.
    • The nature of the salt formed determines whether the solution is acidic, neutral, or basic.
  • A weakly acidic solution can be produced by a strong acid and a weak base, but only if the conjugate acid of the weak base is strong.
  • A solution of a weak acid reacts with a solution of a strong base to form a conjugate base of the weak acid and the strong base.
    • The strong base's conjugate acid is a weaker acid than water and has no effect on the solution's acidity.
    • The weak acid's conjugate base is weak and ionizes in water.
    • This makes the solution slightly basic and increases the amount of hydroxide ion in it.
  • An acidic, basic, or neutral solution can be achieved with a weak acid and a weak base.
    • This is the most complex of the reactions.
    • The solution can be acidic or basic if the conjugate acid and the conjugate base are not equal.
  • It helps us digest food.
    • The acid of the stomach leaking through the muscular valve at the top of the stomach into the lower reaches of the esophagus causes the burning sensation associated with heartburn.
    • The OpenStax book is available for free at http://cnx.org/content/col11760/1.9 from the corrosive effects of stomach acid the way the lining of the stomach is, and the results can be very painful.
    • If we take an antacid, we can reduce the excess acid in the esophagus.
    • Antacids are bases.
    • CaCO3 is one of the most common antacids.
  • Milk of Magnesia is a suspension of magnesium.
  • This reaction doesn't produce carbon dioxide, but magnesium-based antacids can have a laxative effect.
  • The active ingredient in several antacids is aluminum hydroxide.
    • Some antacids use aluminum hydroxide in conjunction with magnesium hydroxide to balance the effects of the two substances.
  • Synthetic chemistry in cooking is safe to eat.
    • There are many examples of acid-base chemistry in the kitchen.
    • Baking soda can be used in baking.
    • The base is NaHCO3.
    • Baking powder is a mixture of two chemicals that come in contact with water in the batter.
  • Many people like to cook fish with acids such as lemon juice and vinegar.
    • Fish have volatile amine in their systems, which are neutralized by acids to yield involatile ammonium salts.
    • The smell of the fish is reduced and the taste is better.
  • A neutralization reaction takes place between the bases in the flesh of fish and the bases in lemons or acetic acid.
  • Pickling is a method used to preserve vegetables.
    • A cucumber is submerged in a brine solution in a sealed jar.
    • The brine solution suppresses the growth of harmfulbacteria and favors the growth of beneficialbacteria.
    • The beneficialbacteria feed on the starches in the cucumber and produce lactic acid as a waste product.
  • The acidity of the brine is increased by the lactic acid, which kills harmfulbacteria.
    • Cucumbers are able to last longer if they are not eaten by harmfulbacteria.
    • The acid in the pickling process makes the vegetables taste sour.
  • The conjugate acid of the weak base is what makes the product a salt.
    • The conjugate acid is weak.
    • Since HCl is a strong acid, the chloride ion has no effect on the solution's acidity.
    • The weak base of Chloride won't accept a protons to a measurable extent.

  • Any base and its conjugate acid or any acid and its conjugate base are held in this relation.
  • An amine is used to make dyes.
    • It is a salt prepared by the weak base aniline and hydrochloric acid.
  • The conjugate acid of a weak base is called the C6H5NH3 ion.
  • The NH3 is 2.3 x 10-3 and the pH is 2.64.
  • The conjugate base of the weak acid is what we get when we neutralize it with a strong base.
  • A weak base is the conjugate base.
    • The solution's acidity is unaffected by the sodium ion.

  • They only report the constants for acids.
  • We are given two of the three concentrations and asked to find the missing one.
    • The process is easy if we can find the equilibrium constant.
  • The ion behaves as a base in this reaction.
  • In the final stages of the problem, we will probably need to convert pOH to pH or H3O+.

  • The solution is neutral.
  • The solution will be acidic.

  • If we measure the pH of the solutions of a variety of metal ion, we will find that they act as weak acids.
    • An example is the aluminum ion.
  • Dissolved in bulk water.
  • The simplification of the formula of the hydronium ion, H3O+ to H+ is similar.
    • The hydrated aluminum ion is a weak acid and donates a protons to a water molecule.

  • The hydrated aluminum ion becomes a weak acid when it reacts with water.
  • The ionization of a cation carrying more than one charge is usually not extensive beyond the first stage.
  • This is a typical acid ionization problem, despite the unusual appearance of the acid.

  • The reaction goes to the right.

  • We can't calculate the extent of the metal ion's ionization because the constants for the different stages are not known.
    • Most hydrated metal ionize other than the alkali metals to give acidic solutions.