\
==Acid: Proton Donors/ Dissociate into H+ ions==
\
==Bases: Proton Acceptors/ Dissociate into OH- ions==
Alkalis: (are bases that dissolve in water)
\
\
Key facts:
\
\
Substances that change colour when added to an acid/alkali are called indicators. They are often in solution form but can also be found as paper
eg. zinc and aluminum oxides
\
==Preparing Soluble Salts==
Method A: Neutralization
\
Method B: Titration
\
==Preparing Insoluble Salts==
Method C: Precipitation
2 soluble salts added to water and mixed
Note: one soluble salt should always be a potassium or sodium solution (eg. potassium sulfate)
Filter out and clean precipitate with distilled water
Dry insoluble salt precipitate in oven
\
\
==Testing Cations==
Cation | Aqueous NaOH | Aqueous Ammonia |
---|---|---|
Aluminum (Al3+) | White soluble precipitate, turns colorless in excess | White precipitate, insoluble in excess |
Ammonium (NH4+) | Pungent ammonium gas produced turns damp red litmus blue | |
Calcium (Ca2+) | White precipitate, insoluble in excess | Faint or no precipitate |
Copper (Cu2+) | ^^Blue precipitate, insoluble in excess^^ | ^^Blue precipitate, soluble in excess to give a dark blue solution^^ |
Iron(II) (Fe2+) | %%green precipitate, insoluble in excess%% | %%green precipitate, soluble in excess%% |
Iron(III) (Fe3+) | ==Reddish-brown precipitate, insoluble in excess== | ==Reddish-brown precipitate, insoluble in excess== |
Zinc (Zn2+) | White precipitate, soluble and turns colorless in excess | White precipitate, soluble and turns colorless in excess |
Chromium (Cr3+) | Grey green precipitate, soluble to give dark green solution in excess | Grey green precipitate, insoluble in excess |
\
==Testing for Anions:==
Sulfate ions (SO42-):
Sulphite ions (SO32-):
\
Chloride (Cl-) | White precipitate |
---|---|
Bromide (Br-) | Cream precipitate |
Iodide (I-) | Yellow precipitate |
\
Nitrate ions (NO3-):
Carbonate ions (CO32-):
\
==Flame Tests==
==Test for Gases:==
Gas | Test result |
---|---|
Ammonia (NH3) | Damp red litmus paper turns blue |
Carbon dioxide (CO2) | Bubble gas through–from colorless to cloudy |
Chlorine (Cl2) | Bleaches red/blue litmus paper |
Hydrogen (H2) | Place lighted splint, squeaky pop |
Oxygen (O2) | Place glowing splint, splint relights |
\