Test for halides and acidification Flashcards
What is added to halides to test for them
Silver nitrate (AgNO3)
Test for fluorine
No reaction with AgNO3
Because Soluble in aq
Forms colourless solution
Test for fluorine
No reaction with AgNO3
Because Soluble in aq
Forms colourless solution
Chlorine full reaction with silver nitrate
NaCl + AgNO3-> NaNO3 + AgCl
(aq) (aq) (aq) (s)
Chlorine ionic equation with silver nitrate
- Cl(aq) + Ag -> AgCl (s)
What colour does chlorine turn when silver nitrate is added to it
White precipitate is formed
Bromine full reaction
NaBr + AgNO3 -> NaNO3 + AgBr
(aq) (aq) (aq) (s)
Bromine ionic reaction with silver nitrate
- Br(aq) + Ag(aq) -> AgBr(s)
What colour does bromine turn when silver nitrate is added
A cream precipitate is formed
Iodine full reaction with silver nitrate
NaI + AgNO3 -> NaNO3 + AgI
(aq) (aq) (aq) (s)
Iodide ionic equation reaction with silver nitrate
- I(aq) + Ag(aq) -> AgI (aq)
What colour does iodide turn when silver nitrate is added
Turns pale yellow
How can you confirm what halide it is as white, cream and pale yellow are all very similar colours
Add dilute/concentrated ammonia depending on what halide you’re confirming
How to confirm for chloride ions
Add DILITE ammonia and if it contains chlorine it will turn colourless
Chlorine confirmation test with ammonia
AgCl(aq) + 2NH3(aq) <—-> Ag[(NH3)2]+(aq) + Cl-(aq)
How to confirm bromide
Add dilute ammonia first to confirm no chloride ions are present if it doesn’t change colour then add concentrated ammonia and if bromide ions are present it should turn colourless
Bromine ammonia confirmation test
AgBr(aq) + 2NH3(aq) <—-> Ag[(NH3)2]+(aq) + Br-(aq)
role of Acidification
To get ride of impurities like Carbonate ions (CO3)2- and hydroxide ions (OH-) by adding HNO3 or AgNO3 to turn them into carbon dioxide and water respectively
Acidification reaction by adding silver nitrate (AgNO3) for the
hydroxide ions
+ -
Ag(aq) + OH(aq) -> AgOH(s)
Acidification reaction with silver nitrate for carbonate ions
+ 2-
Ag(aq) + Co3(aq) -> Ag2CO3 (s)
Acidification reaction by adding nitric acid (HNO3) to OH- ions
+¬¬¬¬¬¬ -¬¬¬¬¬¬¬¬¬-¬¬¬¬¬¬¬¬¬¬¬¬-
H(aq) + NO3(aq) + OH(aq) -> H2O+ NO3
(l) (aq)
Acidification reaction by adding nitric acid (HNO3) to the carbonate ions
+¬¬¬¬¬-¬¬¬¬¬2-
H + NO3 + CO3 -> H2O + CO2 + NO3
(aq) (aq) (aq) (l) (g) (aq)
How can you tell carbonate ions are present when acidifying the solution with nitric acid
CO2 is produced as a gas from the carbonate ions so there should be fizzing
