Chlorine
Cl
atomic number
17
melting point
-101.5°C

1. Mix a small portion of powdered mineral and a bit of pyrolusite (MnO2) with four times as much potassium bisulphate (KHSO4), then place the mixture in a test tube and heat it with a lamp, candle, or Bunsen gas burner; the pungent odor of Cl2 gas will fill the air; (AgCl and chlorine-bearing silicates must be fused with a sodium carbonate flux before performing this test).


2. Mix several small fragments of a silver halide sample with some powdered galena, then place the mixture in a closed tube and heat it with a Bunsen gas burner (any type of lamp or candle will work); if the halogen is chlorine, colorless globules will form which turn white when cool; if the halogen is bromine, yellow globules will appear which also turn white when cool; if the halogen is iodine, a dark orange-red bead will form which turns lemon yellow when cool; if the silver halide sample consists of a mixture of halogens, the results will be obscured.