Tests For Other Cations And Anions

Question 0

Fe2+

Answer 0

Add NaOH

Green ppt formed

Question 1

NH4+

Answer 1

NH4+(aq) + OH-(aq) ➡️NH3(g) + H2O(l)

Ammonia gas turns damp red litmus paper blue (alkaline)

Question 2

Fe3+

Answer 2

Add NaOH

Brown ppt formed

Question 3

Cu2+

Answer 3

Add NaOH

Blue ppt formed

Question 4

Cl-

Answer 4

Add HNO3(aq) (removes other ions which give positive results ie. CO32-, OH-)
Add AgNO3(aq)
Forms white ppt is positive

Question 5

Br-

Answer 5

Add HNO3(aq) (removes other ions which give positive results ie. CO32-, OH-)
Add AgNO3(aq)
Forms cream ppt is positive

Question 6

I-

Answer 6

Add HNO3(aq) (removes other ions which give positive results ie. CO32-, OH-)
Add AgNO3(aq)
Forms yellow ppt is positive

Question 7

SO4-

Answer 7

Add HCl(aq) to remove CO32- and OH- (create false positive)
Add BaCl2(aq)
If present, forms white ppt

Question 8

CO32-

Answer 8

Add acid + collect any gas evolved
Bubble through limewater
If goes cloudy, CO2 present which carbonate produces when reacted with acid