Unknown sample

1. Add water

1.1. Residue

1.1.1. Add sodium hydroxide

1.1.1.1. White precipitate formed, insoluble in excess

1.1.2. Add aqueous ammonia

1.1.2.1. No precipitate formed

1.1.3. Add aqueous sodium hydroxide and warm

1.1.3.1. No gas produced

1.1.4. Add acidified aqueous silver nitrate

1.1.4.1. No precipitate formed

1.1.5. Add acidified aqueous barium nitrate

1.1.5.1. No precipitate formed

1.1.6. Add acidified aqueous lead (II) nitrate

1.1.6.1. No precipitate formed

1.1.7. Add dilute hydrochloric acid, then heat gently

1.1.7.1. Gas produced passed through delivery tube and bubbled into limewater

1.1.7.1.1. Chalky white precipitate formed

1.1.8. Add aqueous sodium hydroxide and devarda's alloy; warm carefully

1.1.8.1. No gas produced

1.2. Filtrate

1.2.1. Add sodium hydroxide

1.2.1.1. White precipitate formed, soluble in excess

1.2.2. Add aqueous ammonia

1.2.2.1. White precipitate formed, soluble in excess

1.2.3. Add aqueous sodium hydroxide and warm

1.2.3.1. Gas produced is pungent and turned damp red litmus paper blue

1.2.4. Add acidified aqueous silver nitrate

1.2.4.1. No precipitate formed

1.2.5. Add acidified aqueous barium nitrate

1.2.5.1. White precipitate formed

1.2.6. Add acidified aqueous lead (II) nitrate

1.2.6.1. No precipitate formed

1.2.7. Add aqueous sodium hydroxide and devarda's alloy; warm carefully

1.2.7.1. Gas produced is pungent and turned damp red litmus paper blue