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Reaction of Phosphorus with Sodium Hydroxide A gas is generated which undergoes spontaneous combustion in the atmosphere.

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Presentation on theme: "Reaction of Phosphorus with Sodium Hydroxide A gas is generated which undergoes spontaneous combustion in the atmosphere."— Presentation transcript:

1 Reaction of Phosphorus with Sodium Hydroxide A gas is generated which undergoes spontaneous combustion in the atmosphere

2 Demonstration n The reactants were heated together in a Florence flask n The phosphine gas bubbled into the water then broke through the surface n Spontaneous combustion occured when the phosphine emerged into the atmosphere

3 Purpose n To produce an unfamiliar gas related to other more familiar gases n To observe the unique property of spontaneous combustion of this gas

4 Concepts 1.Compounds of Non-Metals with Hydrogen 2.Spontaneous Combustion 3.Disproportionation Reactions

5 1.Compounds of Non- Metals with Hydrogen n Hydrogen combines with many non-metals to form familiar compounds  BH 3 borane, an organic reducing agent  CH 4 methane, an organic gas  NH 3 ammonia, used as fertilizer  H 2 O water  H 2 S hydrogen sulfide, rotten-egg gas

6 2.Spontaneous Combustion n Flammable substances are simply those that burn in the presence of oxygen with the evolution of heat n There is enough heat in the surroundings to cause spontaneous combustion of some substances n In this demonstration the highly reactive phosphine gas PH 3 is generated

7 3.Disproportionation Reactions n A single reactant ends up in more than one product n Disproportionation of white phosphorus 3NaOH +P 4 + H 2 O 3NaH 2 PO 2 + PH 3 n In addition to phophine gas, sodium hypophosphite is formed

8 Conclusions n A disproportionation reaction of phosphorus produced phosphine gas n Phosphine gas underwent spontaneous combustion in the atmosphere n 4PH 3 + 8O 2 P 4 O H 2 O + light

9 Comments n Phosphine is extremely poisonous n Phosphine occurs naturally from the putrefaction of organic matter containing phosphorus n Will-o-the-Wisp (flammable swamp gas) of Robert Burns is phosphine n Traces of P 2 H 4 initiate combustion n PH 3 +8O 2 6H 2 O + P 4 O 10 n This demonstration was first performed in 1859 by Gorup-Besanez


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