Test for Cations and Anions

Only available on StudyMode
  • Download(s) : 316
  • Published : January 16, 2013
Open Document
Text Preview
Tests for Cations and Anions with Equations

|CATION |TEST |OBSERVATION | |Copper Cu2+ |Add dilute sodium hydroxide solution | | |e.g. in CuCl2 solution or solid. | |Blue precipitate of copper hydroxide, which does not dissolve in excess NaOH. | |Blue in solution or as a solid. | |CuSO4(aq) + 2NaOH(aq) ( Cu(OH)2(s) + Na2SO4(aq) | | | |Or Cu2+ + 2OH- ( Cu(OH)2(s) | |Iron (II) Fe2+ |Add dilute sodium hydroxide solution | | |e.g. in FeCl2 solution or as a solid. Often pale green | |A dark green gelatinous precipitate is formed that does not dissolve in excess NaOH. | |in colour. | |It turns brown on standing as it is oxidised in air to Fe(III) hydroxide, Fe(OH)3. | | | |FeCl2(aq) + 2NaOH(aq) ( Fe(OH)2 (s) + 2NaCl(aq)...
tracking img