Arkansas State University
Department of Chemistry
and Physics
Study Guide
Acids and Bases 

Properties of Acids in aqueous solutions

                    1. Tastes sour

                    2. Change litmus paper to red

                    3. Conduct electricity

                    4. Some react with metals to give hydrogen gas

                    5. React with metal oxides and hydroxides to form
                    salts and water

                    6. React with salts of weaker acids to form the weaker
                    acid and new salts

Properties of Bases in aqueous solutions

                    1. Taste bitter

                    2. Feel slippery

                    3. Change litmus paper to blue

                    4. Conduct electricity

                    5. React with acids to form salts and water

Acid-Base Theories:

            Arrhenius

                        Acid - contains hydrogen and produces H+ ions when dissolved in water

                        Base - contains hydroxide and produces OH- ions when dissolved in water

        Bronsted-Lowry

                        Acid - donates H+ ions or proton donor

                        Base - accepts H+ ions or proton acceptor

        Lewis

                        Acid - accepts electron pair

                        Base - donates electron pair

Acid Strengths

     Binary acids (HF, HCl, H2S, etc.)

          Going down a column, rule is: the higher bond energy, the weaker the acid

                                Example:   HF < HCl < HBr < HI

           Going across a row, rule is:  the higher the electronegativity, stronger the acid

                                Example:   HF > H2O > NH3 > CH4

     Ternary acids (HNO3, H2SO4, HClO4, etc.)

          For cases with the same central atom, acid strength increases with the number of
          oxygen atoms

                               Example:   HClO4 > HClO3 > HClO2 > HClO

          For cases with different central atom and the same number of oxygen atoms, acid
          strength increases with electronegativity of the central atom

Example:    HClO4 > HBrO4 > HIO4