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Identification of ions and gases - Coggle Diagram
Identification of ions and gases
Anion Test
Add dilute acid
Carbonate: Effervescence, carbon dioxide produced
Acidify with dilute nitric acid, then aqueous silver nitrate
Chloride: White precipitate, Bromide: Cream precipitate, Iodide: Yellow precipitate
Add aqueous sodium hydroxide then aluminum foil; warm carefully
Nitrate: Ammonia produced (turns damp red litmus paper blue)
Acidify, then add aqueous barium nitrate or barium chloride
Sulfate: White precipitate
Add dilute hydrochloric acid, warm gently and test for the presence of sulfur dioxide
Sulfite: Sulfur dioxide produced will turn acidified aqueous potassium manganate (VII) from purple to colorless
Gases Test
Ammonia: Turn damp red litmus paper blue
Oxygen: Relights a glowing splint
Sulfur dioxide: Turns acidified aqueous potassium manganate (VII) from purple to colorless
Hydrogen: Pops with a lighted splint
Chlorine: Bleaches damp litmus paper
Carbon dioxide: Turns limewater milky
Cation Test
Adding aqueous sodium hydroxide
Aluminium: white precipitate, soluble in excess, gives a colorless solution
Ammonium: ammonia gas produced on heating, turns red litmus blue
Calcium: white precipitate, insoluble in excess
Chromium(III): green precipitate, soluble in excess, gives a green solution
Copper(II): light blue precipitate, insoluble in excess
Iron(II): green precipitate, insoluble in excess
Iron(III): green precipitate, insoluble in excess
Zinc(II): white precipitate, soluble in excess, gives a colorless solution
Adding aqueous ammonia
Aluminium: white precipitate, insoluble in excess
Calcium: no precipitate, or very slightly white precipitate
Chromium(III): grey-green precipitate, soluble to some extent in excess, gives blue solution
Copper(II): light blue precipitate, soluble in excess, gives a dark blue solution
Iron(II): green precipitate, insoluble in excess
Iron(III): red-brown precipitate, insoluble in excess
Zinc(II): white precipitate, soluble in excess, gives a colorless solution
Flame tests for metal cations
Lithium: red
Sodium: yellow
Potassium: lilac
Copper(II): blue-green
Barium: green
Calcium: orange-red