Ion Tests

Question 1

Test & Observation & Equation:
Carbonate Test:
CO3²-

Answer 1

Add Dilute HNO3
Fizzing (CO2 produced)
CO3²- + 2H+ > CO2 + H2O

Question 2

Test & Observation & Equation:
Sulfate Test:
SO4²-

Answer 2

Add Ba(NO3)2
White Precipitate (BaSO4)
Ba²+ + SO4²- > BaSO4

Question 3

Test & Observation & Equation:
Ammonium Test:
NH4+

Answer 3

Heat w/ NaOH
NH3(g) produced, turns litmus paper blue
NH4+ + OH- > NH3 + H20

Question 4

Test & Observation & Equation & NH3 solubility:
Chloride Ion:
Cl-

Answer 4

Add HNO3 then AgNO3
White Precipitate (AgCl)
Ag+ + Cl- > AgCl
Soluble in Dilute NH3

Question 5

Test & Observation & Equation & NH3 solubility:
Bromide Ion:
Br-

Answer 5

Add HNO3 then AgNO3
Cream Precipitate (AgBr)
Ag+ + Br- > AgBr
Soluble in Conc. NH3

Question 6

Test & Observation & Equation & NH3 solubility:
Iodide Ion:
I-

Answer 6

Add HNO3 then AgNO3
Yellow Precipitate (AgI)
Ag+ + I- > AgI
Insoluble in Conc. NH3

Question 7

Why is Dilute HNO3 added to Halide Tests before AgNO3?

Answer 7

Acid is added to remove any carbonates that could produce a white solid: Ag2CO3 (False Positive)

Must be HNO3 as:
HCL would produce AgCl (False positive)
H2SO4 would produce white solid: Ag2SO4 (False Positive)

Question 8

Order of Ionic Tests?

Answer 8

Carbonates > Sulfates > Halides > Ammonium

Question 9

Order of Ionic Tests?

Answer 9

CO3²- > SO4²- > X- > NH4+