Ion tests Flashcards
What is the test to identify carbonate? (CO3 2-)
Add a dilute inorganic acid (e.g HCL), bubble any evolved gas into a test tube cintaining limewater. If carbonate present, limewater will turn milky
What is the test to identify Sulphate (SO4 2-)?
Add Ba(NO3)2 solution. A white precipitate indicates the presence of sulphate. Ensure that carbonate is absent by testing with dilute acid.
what is the test to identify nitrate? (NO3 2-)
Treat with concentrated H2SO4 and add a few trimmings of Cu. Brown pungent fumes of NO2 (g) indicate that nitrate is present
what is the test for chloride?
add a solution of AgNO3. a white precipitate which turns purple on exposure to light indicates presence
What is the test for Phosphate? (PO4 3-)
a yellow precipitate formed on warming with a solution of ammonium molybdate and nitric acid
What is the test for Barium Ba2+?
carry out a flame test. A Pt wire is mounted in a glass holder, dipped in concentrated HCl and then cleaned in the non- luminous bunsen flame. clean pt wire is dipped in the sample to be tested. Ba 2+ turns flame APPLE GREEN
what is the test for calcium Ca 2+?
brick red colour to the flame
What is the test for copper Cu 2+?
Add NH4OH and a deep blue complex ion forms if copper is present
What is the test for lead? Pb 2+
- add dilute HCl. a white precipitate of PbCl3 forms which dissolves in hot water
- add KI (potassium iodide) and a yellow precipitate of PBI2 forms
What is the test for iron 2+ (Fe 2+)?
- forms a white precipitate when NaOH is added. Precipitate rapidly turns brown
- forms a deep blue precipitate with potassium ferricyanide
What is the test for iron 3+ (Fe 3+)?
- forms a red-brown precipitate of Fe(OH)3 when NaOH is added
- forms a blood -red complex when potassium thiocyanate solution is added
