Cation Anion Tests

Tests for Anions Tests for chloride | ClAdd silver ions and you get a white ppt. of silver chloride. When you add dilute nitric acid or barium nitrate there is no reaction. Tests for carbonate | CO3 2Add dilute nitric acid and bubbles of carbon dioxide gas evolve. Add silver nitrate solution and get a yellow ppt. of silver carbonate. Add barium nitrate and get a white ppt. of barium carbonate. Tests for phosphate | PO43Add silver nitrate solution and get yellow ppt. of silver phosphate. Add barium nitrate and get a white ppt. of barium phosphate. No reaction for nitric acid. Tests for sulphate | SO42Add silver nitrate and there will be no ppt. or faint white ppt. silver sulphate is sparingly soluble. Add barium nitrate and get a dense white ppt. of barium sulphate. No reaction for nitric acid. Common Gas Tests 1. Oxygen (O2) – relights glowing splint. 2. Carbon dioxide (CO2) – turns limewater (saturated calcium hydroxide) chalky/milky – forms insoluble calcium carbonate. 3. Hydrogen (H2) – extinguishes lighted splint with a ‘pop’ sound. 4. Ammonia (NH3) – aqueous ammonia turns red litmus paper blue. 5. Chlorine (Cl2) – turn moist litmus or universal indicator paper red, and then bleach it white. 6. Sulphur Dioxide (SO2) – turn acidified potassium dichromate (VI) from orange to green. 7. Alkene (CnH2n) – decolourises aqueous bromine solution.

Cations and Anions Specific Tests Qualitative Analysis and Tests for Common Gases Sam Yong | 24 Sep 2008

Tests for Cations Tests for lead | Pb2+ Add dilute hydrochloric acid and get insoluble white ppt. of lead (II) chloride which dissolves on heating. Add dilute sulphuric acid and get a insoluble white ppt. of lead (II) sulphate. Add dilute sodium hydroxide and get a white ppt. of lead (II) hydroxide. Test for copper | Cu2+ Add dilute sodium hydroxide and get an insoluble blue ppt. of copper (II) hydroxide. -> No reaction if hydrochloric acid or sulphuric acid was used. Test for iron (II)/ferrous ions | Fe 2+ Add dilute sodium hydroxide and get a pale green ppt. of iron (II) hydroxide. -> turns brown quickly. -> No reaction if hydrochloric acid or sulphuric acid was used. Test for iron (III)/Ferric ions | Fe3+ Add dilute sodium hydroxide and get a reddish brown ppt. of iron (III) hydroxide. -> No reaction if hydrochloric acid or sulphuric acid was used. Test for calcium ions | Ca2+ Add dilute sulphuric acid and get an insoluble white ppt. of calcium sulphate. React calcium chloride and sodium hydroxide to get a faint white ppt. of sparingly soluble calcium hydroxide. -> No reaction if hydrochloric acid was used. Tests for barium ions | Ba2+ Add dilute sulphuric acid and get an insoluble white ppt. of barium sulphate. -> No reaction if hydrochloric acid or sodium hydroxide was used.

Cations and Anions Specific Tests Qualitative Analysis and Tests for Common Gases Sam Yong | 24 Sep 2008