In chemical reaction, when one component each of both the reacting species are exchanged to form the products then such reactions are said to be a double displacement reaction.
The reaction that occur on mixing the solution of [tex]KOH(aq)[/tex] with [tex]Fe(NO_3)(aq)[/tex] is an example of double displacement reaction:
[tex]KOH(aq)+ Fe(NO_3)(aq) \rightarrow Fe(OH)_3(s)+KNO_3(aq)[/tex]
The balanced chemical equation is:
[tex]3KOH(aq)+ Fe(NO_3)(aq) \rightarrow Fe(OH)_3(s)+3KNO_3(aq)[/tex]
Hence, [tex]Fe(OH)_3[/tex] will precipitate as solid in the reaction.
