Cation and Anion Identification? (1 Viewer)

[Newbit]

Hello Everyone, I was just wondering if the identification of anion and cation will be needed for the HSC Chemistry exam, as in does it come up often in the exam and is it worth studying? If so what are the anions and cations that we need to know?

 

[deswa1]

Yeah its in the syllabus so it can definitely come up. You need to know how to test for:

phosphate, sulfate, carbonate, chloride, barium, calcium, lead, copper, iron

 

[DefiningTheta]

don't forget the flame tests as well.

 

[Newbit]

Yeah its in the syllabus so it can definitely come up. You need to know how to test for:

phosphate, sulfate, carbonate, chloride, barium, calcium, lead, copper, iron

For Iron do you need to know the test for both Fe2+ and Fe3+?

 

[ellie95]

For Iron do you need to know the test for both Fe2+ and Fe3+?

Yeah you do

Fe2+ >>>>>> White ppt with OH- but quickly turns brown
Fe3+>>>>>> Blood red ppt with SCN-

 

[someth1ng]

Yeah its in the syllabus so it can definitely come up. You need to know how to test for:

phosphate, sulfate, carbonate, chloride, barium, calcium, lead, copper, iron

This is correct.

There's many different ways to do it but the way I do it is the HSCOnline method.

For anions:
1. Add Fe3+ (brown ppt of OH-)
2. Add Fe2+ (ppt is of CO3 2- or PO4 3+ --> Add acid and carbonates will produce effervescence of CO2)
3. Add Ba2+ (white ppt of SO4 2-)
4. Add Pb2+ (white ppt of Cl-)

For cations:
1. Add Cl- (white ppt for Pb2+, grey ppt that darkens for Ag+)
2. Add SO4 2- (white ppt for Ca2+ and Ba2+ --> flame test)
3. Add OH- (ppt of Cu2+ and Fe2+ and Fe3+ --> Add NH3 in copper and a blue solution is produced, Fe2+ is green but turns brown, Fe3+ is only brown)

 

[Nuggos]

remember those and your flame tests