29. The chemical equations below show the reaction of Al(OH)3 as a Lewis acid and as a Lewis base, respectively.
Al(OH)3(s) + OH–(aq)    Al(OH)4–(aq)
Al(OH)3(s) + 3 H3O+(aq)    Al3+(aq) + 3 H2O(  )
Substances that can behave as either Lewis acids or bases are called ________ substances.

Answer:



30. The following reaction occurs spontaneously.
2 H+(aq) + Ca(s)  Ca2+(aq) + H2(g)
Write the balanced oxidation half-reaction.

a. 2 H+(aq) + 2 e–  H2(g)
b. 2 H+(aq)  H2(g) + 2 e–
c. H2(g)  2 H+(aq) + 2 e–
d. Ca(s) + 2 e–  Ca2+(aq)
e. Ca(s)  Ca2+(aq) + 2 e–