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Lesson 2: Ionic and Molecular Compounds

5. Acids and Bases

Acids 

Empirically, acids are aqueous molecular compounds of hydrogen that form electrically conductive solutions. Acids;

  • turn blue litmus paper red
  • react with most metals (Zn and Mg) to produce H2(g) and neutralize bases
  • taste sour
Acids are named in several different ways based on anion endings (-ide, -ate, -ite).
Formula Theoretical Ionic Name Traditional Name
HCl hydrogen chloride  hydrochloric acid
H2SO4  hydrogen sulfate sulfuric acid 
HNO2  hydrogen nitrite  nitrous acid 
IUPAC updates suggest that acids be named simply by putting the word 'aqueous' in front of the theoretical ionic name. 
FormulaTheoretical Ionic name UPACTraditional name
HClO hydrogen hypochlorite aqueous hydrogen hypochlorite  hypochlorous acid 
HCl hydrogen chloride  aqueous hydrogen chloride hydrochloric acid 



Bases 

Empirically, bases are aqueous ionic hydroxides that form electrically conductive solutions and turn red litmus paper blue. Bases;

  • turn red litmus paper blue
  • taste bitter and feel slippery
  • neutralize acids

Bases are present in the form of alkali metal or alkaline-earth hydroxides. They are named in a very similar way to ionic compounds. Study the following examples. 
Ca(OH)2: calcium hydroxide
NaOH: sodium hydroxide
KOH: potassium hydroxide
Bases are present in the form of transition metal hydroxides, the name will use different suffixes since transition metal has two oxidation states. The state with the lower number is given an -ous, the state with the greater number is given -ic suffix.

FormulaClassis NameUPAC
CuOH Cuprous hydroxide Copper (I) hydroxide
Cu(OH)2 Cupric hydroxide Copper(II) hydroxide
 
Be sure to study textbook p. 34-35