19.1

LESSON OBJECTIVES

• Describe the properties of acids and bases
• Describe the properties of acids and bases
• Define an acid and a base according to the Arrhenius theory
• Define an acid and a base according to the Brønsted-Lowry theory. Be able to identify the conjugate acid-base pairs in a Brønsted-Lowry acid-base reaction
• Define an acid and a base according to the Lewis theory

ACID-BASE PROPERTIES

• Acids are common in food
• hydrochloric acid is used to digest food
• Many cleaners contain ammonia

ACIDS

• Aqueous solutions of acids are electrolytes
• Acids have a sour taste
• Acids change the color of certain acid-base indicators
• Acids react with active metals to yield hydrogen gas
• Acids react with bases to produce a salt and water

BASES

• Aqueous solutions of bases are also electrolytes
• Bases often have a bitter taste and are found in foods less frequently than acids
• Bases also change the color of indicators
• Bases do not react with metals in the way that acids do
• Bases react with acids to produce a salt and water

Arrhenius Acids and Bases

• Arrhenius acid is a compound which ionizes to yield hydrogen ions (H+) in aqueous solution
• Arrhenius base is a compound which ionizes to yield hydroxide ions (OH−) in aqueous solution

ARRHENIUS ACIDS

• hydronium ion (H3O+) can be thought of as a water molecule with an attached hydrogen ion
• monoprotic acid is an acid that contains only one ionizable hydrogen
• polyprotic acid is an acid that contains multiple ionizable hydrogens

ARRHENIUS BASES

• Bases are ionic compounds which yield the hydroxide ion (OH−) upon dissociating in water
• Bases that consist of an alkali metal cation and the hydroxide anion are all very soluble in water

Brønsted-Lowry Acids and Bases

• Brønsted-Lowry acid is a molecule or ion that donates a hydrogen ion in a reaction
• Brønsted-Lowry base is a molecule or ion that accepts a hydrogen ion in a reaction

Untitled Slide