Cations, Anions, Tests for Gases, and Flame Tests for Metal Ions Flashcards
Test and result for carbonate, CO3^2−
Test: add dilute acid then test for carbon dioxide
gas
Result: effervescence, carbon dioxide produced
Test and result for chloride, Cl−
[in solution]
Test: acidify with dilute nitric acid, then add
aqueous silver nitrate
Result: white ppt.
Test and result for bromide, Br −
[in solution]
Test: acidify with dilute nitric acid, then add
aqueous silver nitrate
Result: cream ppt.
Test and result for iodide, I−
[in solution]
Test: acidify with dilute nitric acid, then add
aqueous silver nitrate
Result: yellow ppt.
Test and result for nitrate, NO3–
[in solution]
Test: add aqueous sodium hydroxide, then
aluminium foil; warm carefully
Result: ammonia produced
Test and result for sulfate, SO4^2−
[in solution]
Test: acidify with dilute nitric acid, then add aqueous barium nitrate
Result: white ppt.
Test and result for sulfite, SO3^2−
Test: add a small volume of acidified aqueous potassium manganate(VII)
Result: the acidified aqueous potassium manganate(VII) changes colour from purple to colourless
aluminium, Al3+
effect of aqueous sodium hydroxide: white ppt., soluble in excess, giving a colourless solution
effect of aqueous ammonia: white ppt., insoluble in excess
ammonium, NH4+
effect of aqueous sodium hydroxide: ammonia produced on warming
effect of aqueous ammonia: —
calcium, Ca2+
effect of aqueous sodium hydroxide: white ppt., insoluble in excess
effect of aqueous ammonia: no ppt. or very slight white ppt.
chromium(III), Cr3+
effect of aqueous sodium hydroxide: green ppt., soluble in excess
effect of aqueous ammonia: green ppt., insoluble in excess
copper(II), Cu2+
effect of aqueous sodium hydroxide: light blue ppt., insoluble in excess
effect of aqueous ammonia: light blue ppt., soluble in excess, giving a dark blue solution
iron(II), Fe2+
effect of aqueous sodium hydroxide: green ppt., insoluble in excess, ppt. turns
brown near surface on standing
effect of aqueous ammonia: green ppt., insoluble in excess, ppt. turns brown near surface on standing
iron(III), Fe3+
effect of aqueous sodium hydroxide: red-brown ppt., insoluble in excess
effect of aqueous ammonia: red-brown ppt., insoluble in excess
zinc, Zn2+
effect of aqueous sodium hydroxide: white ppt., soluble in excess, giving a colourless solution
effect of aqueous ammonia: white ppt., soluble in excess, giving a colourless solution
Gas test: ammonia, NH3
turns damp red litmus paper blue
Gas test: carbon dioxide,
CO2
turns limewater milky
Gas test: chlorine, Cl2
bleaches damp litmus paper
Gas test: hydrogen, H2
‘pops’ with a lighted splint
Gas test: oxygen, O2
relights a glowing splint
Gas test: sulfur dioxide, SO2
turns acidified aqueous potassium manganate(VII) from purple to colourless
Flame test: lithium, Li+
Red
Flame test: sodium, Na+
Yellow
Flame test: potassium, K+
Lilac
Flame test: calcium, Ca2+
Orange-red
Flame test: barium, Ba2+
Light green
Flame test: copper(II), Cu2+
Blue-green
