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Qualitative Analysis Cations Internal Assessment 2.1- part one

Qualitative Analysis Cations Internal Assessment 2.1- part one. First step:. add 2 drops of dilute NaOH(aq). Record your results clearly. add 2 drops of dilute NaOH solution. no precipitate Na +. add 2 drops of dilute NaOH solution.

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Qualitative Analysis Cations Internal Assessment 2.1- part one

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  1. Qualitative Analysis Cations Internal Assessment 2.1- part one

  2. First step: add 2 drops of dilute NaOH(aq) Record your results clearly

  3. add 2 drops of dilute NaOH solution. no precipitateNa+

  4. add 2 drops of dilute NaOH solution. white precipitate formsAl3+, Zn2+, Pb2+, Mg2+, Ba2+ add excessNaOH solution precipitate disappearsAl3+, Zn2+, Pb2+ precipitate remainsMg2+, Ba2+

  5. Equations needed for Merit and Excellence white precipitate formsAl3+, Zn2+, Pb2+, Mg2+, Ba2+ Mg2+(aq) + 2 OH(aq) Mg(OH)2(s) Add the equations for the rest of the cations. Equations needed for Excellence precipitate disappearsAl3+, Zn2+, Pb2+ Zn(OH)2(s) + 2 OH(aq) [Zn(OH)4]2(aq) Zn2+(aq) + 4 OH(aq) [Zn(OH)4]2(aq) Add the equations for Al3+ and Pb2+ .

  6. Is it Mg2+ or Ba2+? precipitate remainsMg2+, Ba2+ New solution in a clean test tube!!!! add dilute H2SO4 solution colourless solutionMg2+ white precipitateBa2+ Equation needed for Merit and Excellence SO42(aq) + Ba2+(aq) BaSO4(s)

  7. precipitate disappearsAl3+, Zn2+, Pb2+ NH3 is a base NH3 provides OH- ions in solution Write down the 3 equations for the precipitates. New solution in a clean test tube!!!! add 2 drops, thenexcess NH3 solution Equations needed for Merit and Excellence white precipitate forms and disappears, Zn2+ Equation needed for Excellence white precipitate formsAl3+, Pb2+ Zn(OH)2(s) + 4 NH3(aq) [Zn(NH3)4]2+ (aq) + 2 OH(aq) Zn2+(aq) + 4 NH3(aq) [Zn(NH3)4]2+(aq)

  8. Is it Al3+ or Pb2+? white precipitate formsAl3+, Pb2+ New solution in a clean test tube!!!! add dilute H2SO4 solution Equations needed for Merit and Excellence colourless solutionAl3+ white precipitatePb2+ Pb2+(aq) + SO42(aq) PbSO4(s)

  9. add 2 drops of dilute NaOH solution. green precipitate formsFe2+ Equation needed for Merit and Excellence Write down the equation for this reaction.

  10. add 2 drops of dilute NaOH solution. add 2 drops KSCN solution orange precipitate formsFe3+ dark red solution confirms Fe3+ New solution in a clean test tube for confirmatory test Equation needed for Merit and Excellence Fe3+(aq) + 3 OH(aq) Fe(OH)3(s) Equation needed for Excellence Fe3+(aq) + SCN(aq) [FeSCN]2+(aq)

  11. add 2 drops of dilute NaOH solution. blue precipitate formsCu2+ add 2 drops, then excessNH3 solution blue precipitate then deep blue solution Cu2+ New solution in a clean test tube for confirmatory test Clear solution !!!! Write down the equation for this reaction. The complex ion is: [Cu(NH3)4]2+ Equation needed for Merit and Excellence Write down the equation for this reaction. Equation needed for Excellence

  12. add 2 drops of dilute NaOH solution. brown precipitate formsAg+ add 2 drops, then excessNH3 solution brown precipitate then colourless solution Ag+ New solution in a clean test tube for confirmatory test Clear solution !!!! Write down the equation for this reaction. The complex ion is: [Ag(NH3)2] + Equation needed for Merit and Excellence Write down the equation for this reaction.

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