`-Answer:`
`a.2NaOH+CuCl_2→2NaCl+Cu(OH)_2`
`→pt ion: Cu^{2+} + 2OH^{-} →Cu(OH)_2`
`b.Fe(NO_3)_2+2KOH→Fe(OH)_2+2KNO_3`
`→pt ion: Fe^{2+} + 2OH^{-} → Fe(OH)_2`
`c.Fe_2(SO_4)_3+6NaOH→2Fe(OH)_3+3Na_2SO_4`
`→pt ion: Fe^{2+} + 3OH^{-} → Fe(OH)_3`
`d.NH_4Cl+AgNO_3→AgCl+NH_4NO_3`
`→pt ion: Ag^{+} + Cl^{-} → AgCl`