Cation Flowchart Flashcards

Flashcards covering key tests and identification methods for various cations based on the cation flowchart lecture.

Ag+ ion

Reacts with HCl to form AgCl white precipitate, which dissolves in NH3 and re-precipitates with HNO3.

Ions precipitated by NH3 + NH4Cl

Fe3+ (rust-colored ppt), Al3+ (white ppt), Cr3+ (green-gray ppt).

Fe3+ confirmatory test

Addition of K4[Fe(CN)6] forms a Prussian blue precipitate.

Al3+ confirmatory test

Amphoteric in NaOH, then with aluminon dye forms a red lake precipitate.

Cr3+ confirmatory test

Oxidize with NaOH + H2O2 to form yellow chromate, then add BaCl2 to form yellow BaCrO4.

Reagent to separate Ca2+

(NH4)2C2O4, forming CaC2O4 white precipitate; confirmed by a brick-red flame test.

Ni(OH)2 color

Green precipitate.

Ni2+ confirmatory test

Reacts with DMG (dimethylglyoxime) to form red Ni(DMG)2.

Mg2+ confirmatory test

Forms Mg(OH)2 white precipitate, then reacts with Mg reagent to form a blue lake.

Zn2+ confirmatory test

Forms Zn(OH)2 which dissolves in excess NaOH; adding K4[Fe(CN)6] then forms a gray-blue precipitate.

NH4+ identification

Reacts with NaOH upon heating to produce NH3 gas.

Na+ identification

Produces a yellow flame in a flame test.