Identifying Substances

Identifying Substances

Flame Tests

Flame Tests are tests that test for positive ions in a metal.

Lilac Flame= Potassium (K+)

Apple Green Flame= Barium (Ba2+)

Red Flame= Lithium (Li+)

Brick Red= Calcium (Ca2+)

Yellow Flame= Sodium (Na+)

Testing positive ions with sodium hydroxide

Positive Ions Symbol ppt colour does it dissolve

Aluminium Al3+ clear-cloudy yes

Calcium Ca2+ clear-white no

Magnesium Mg2+ clear-lilac no

Copper Cu2+ blue no

Iron II Fe2+ green no

Iron III Fe3+ brown no

Testing for Halide Ions

To test for Halide Ions, firstly, you need to acidify the solution with HNO3. Then you add a few drops of silver nitrate and if a precipitate forms, look at its colour to identify your halide...

Halogens Formula Halide Ion Formula Colour of ppt.

Chlorine Cl chloride Cl- white

Bromine Br bromide Br- cloudy/cream

Iodine I iodide I- cloudy yellow

Testing for Sulfate Ions

Sulfate ions are present in sulfuric acid (H2SO4) and copper sulfate (CuSO4). They have the formula SO4-.

To test for sulfate ions, firstly, you acidify the solution with HCl. Next…