A plastic bottle was filled with the mixture of chlorine and hydrogen gases with the desired ratio, achieved by pushing out water in corresponding volume. Chlorine was obtained by reaction of potassium permanganate (KMnO4) with concentrated hydrochloric acid (~35% HCl); hydrogen was bubbled into the plastic bottle directly from a hydrogen balloon.
At room temperature, the mixture of chlorine and hydrogen is quite stable, however, when exposed to ultraviolet radiation, it explodes. As the ultraviolet light source, an ordinary table lamp equipped with a special 300W ultraviolet light bulb was used.
Chlorine reacts with hydrogen, yielding gaseous hydrogen chloride (HCl):
H2(g) + Cl2(g) → 2HCl(g)
As chlorine and hydrogen chloride are both toxic and irritant gases, the experiment was carried out under a fume hood! Hydrogen is highly flammable!
2) CHLORINE: “Preparation of chlorine”