Question

Which of these compounds is not a base?
CsOH
NH4OH
Fe(OH)2
HBr

Answer 1

A very simple (some say too simple) definition of bases and acids is as follows:
Bases are compounds that donate OH- to a solution.
Acids are compounds that donate H+ to a solution.
So which of these compounds may act as an acid or a base.

Answer 2

Fe(OH)2