Chemistry 0620 - Identification of Ions

Vocabulary flashcards covering the identification tests and observations for qualitative anions and aqueous cations based on Chemistry 0620 notes prepared by Bilqees Asif.

Carbonate ($CO_3^{2-}$) Test

A test where dilute acid is added to the sample and tested for carbon dioxide gas; result is effervescence with carbon dioxide produced.

Chloride ($Cl^-$) Test

A test where the solution is acidified with dilute nitric acid, then aqueous silver nitrate is added; result is a white ppt. of AgCl (silver chloride).

Bromide ($Br^-$) Test

A test where the solution is acidified with dilute nitric acid, then aqueous silver nitrate is added; result is a cream ppt. of AgBr (silver Bromide).

Iodide ($I^-$) Test

A test where the solution is acidified with dilute nitric acid, then aqueous silver nitrate is added; result is a yellow ppt. of AgI (silver Iodide).

Nitrate ($NO_3^-$) Test

A test where aqueous sodium hydroxide and aluminium foil are added and warmed carefully; result is ammonia produced.

Sulfate ($SO_4^{2-}$) Test

A test where the solution is acidified with dilute nitric acid, then aqueous barium nitrate is added; result is a white ppt. of $BaSO_4$ (Barium Sulfate) precipitated.

Sulfite ($SO_3^{2-}$) Test

A test where a small volume of acidified aqueous potassium manganate(VII) is added; result is the acidified aqueous potassium manganate(VII) changes colour from purple to colourless.

Aluminium ($Al^{3+}$)

An aqueous cation that forms a white ppt., soluble in excess giving a colourless solution with aqueous sodium hydroxide, and a white ppt., insoluble in excess with aqueous ammonia.

Ammonium ($NH_4^+$)

An aqueous cation that produces ammonia gas on warming with aqueous sodium hydroxide.

Calcium ($Ca^{2+}$)

An aqueous cation that forms a white ppt., insoluble in excess with aqueous sodium hydroxide, and no ppt. or a very slight white ppt. with aqueous ammonia.

Chromium(III) ($Cr^{3+}$)

An aqueous cation that forms a green ppt., soluble in excess with aqueous sodium hydroxide, and a green ppt., insoluble in excess with aqueous ammonia.

Copper(II) ($Cu^{2+}$)

An aqueous cation that forms a light blue ppt., insoluble in excess with aqueous sodium hydroxide, and a light blue ppt., soluble in excess giving a dark blue solution with aqueous ammonia.

Iron(II) ($Fe^{2+}$)

An aqueous cation that forms a green ppt., insoluble in excess with both aqueous sodium hydroxide and aqueous ammonia, where the ppt. turns brown near surface on standing.

Iron(III) ($Fe^{3+}$)

An aqueous cation that forms a red-brown ppt., insoluble in excess with both aqueous sodium hydroxide and aqueous ammonia.

Zinc ($Zn^{2+}$)

An aqueous cation that forms a white ppt., soluble in excess giving a colourless solution with both aqueous sodium hydroxide and aqueous ammonia.