Question

Question #c9e57

Answer 1

Because they can accept protons (= `H^+`)

Explanation:

Example:
Iron(II) oxide does not ionize into `OH^-` ions, but it will accept protons from an acid.
`FeO+2H_3O^+ ->Fe^(2+) +3H_2O`
or more simply:
`FeO+2H^+ ->Fe^(2+)+H_2O`

Another one:
`NH_3+H_2OrightleftharpoonsNH_4^+ +OH^-`
Where `NH_3` snatches an `H^+` from the water molecule, to leave an `OH^-` ion.