Acids, salts and bases

• Soluble salts


  All Nitrates<|>All halides EXCEPT AgCl and PbCl2<|>All sulfates EXCEPT CaSO4, BASO4, PbSO4<|>All group 1 metals salts<|>All ammonium salts
• Insoluble salts


  Silver and lead chlorides (AgCl & PbCl2)<|>Calcium, barium and lead VS. sulphates (CaSO4, BASO4, PbSO4)<|>All carbonates EXCEPT group 1 metals and ammonium carbonates
• Preparing soluble salts: Displacement Method (Excess Metal Method)

  1. Add metal to acid

  2. Obtain salt solution

  3. Evaporate to get salt powder

  4. Crystallise to get salt crystals
• Bubbles of colorless gas (hydrogen) evolve during the displacement reaction
• Tests for gases


  Ammonia: Turns damp red litmus paper blue<|>Carbon dioxide: Turns limewater milky<|>Oxygen: Relights a glowing splint<|>Hydrogen: 'Pops' with a lighted splint<|>Chlorine: Bleaches damp litmus paper<|>Nitrogen dioxide: Turns damp blue litmus paper red<|>Sulfur dioxide: Turns acidified aqueous potassium dichromate(VI) from orange to green
• Tests for anions


  Carbonate: Add dilute acid, effervescence, carbon dioxide produced<|>Chloride: Acidify, add silver nitrate, white ppt.<|>Iodide: Acidify, add silver nitrate, yellow ppt.<|>Nitrate: Add NaOH, then Al foil, ammonia produced<|>Sulfate: Acidify, add barium nitrate, white ppt.
• Tests for aqueous cations

  Aluminium: White ppt. with NaOH, soluble in excess<|>Ammonium: Ammonia produced on warming<|>Calcium: White ppt. with NaOH, no ppt. with NH3<|>Copper: Light blue ppt. with NaOH and NH3<|>Iron(II): Green ppt. with NaOH, red-brown ppt. with NH3<|>Iron(III): Red-brown ppt. with NaOH and NH3<|>Zinc: White ppt. with NaOH, soluble in excess, green ppt. with NH3