Reaction of White Phosphorus and Chlorine

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Reaction of White Phosphorus and Chlorine
Upon being brought together a lump of
white phosphorus and chlorine gas react in flame.
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Purpose

• To observe a combination reaction
• between two non-metals
• To understand that a combination
• reaction is a redox reaction

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Demonstration

• There was a brief induction period before the
  phosphorus began to burn in the chlorine
• The white coating on the inside of the florence
  flask was the product of the reaction, solid
  phosphorus pentachloride

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Concepts

• 1. Allotropes
• 2. Covalent Compounds
• 3. Combination Reactions

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1. Allotropes

• Different forms of the same element
• Carbon
• graphite
• diamond
• Phosphorus
• white phosphorus P4
• red phosphorus

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2. Covalent Compounds

• As opposed to ionic compounds
• Composed of two or more non-metals
• Examples
• carbon oxygen
• phosphorus oxygen
• phosphorus chlorine
• Shared electrons between the elements are
  themselves what we call covalent bonds

CO CO2
P4O10
PCl5
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3. Combination Reactions

• A B C
• P4(s) Cl2(g) PCl5(s)
• Oxidation Number Changes
• Start Finish Effect
• P 0 5 loses electrons
• Cl 0 1- gains electrons

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10
is oxidized
is reduced
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Conclusions

• Two non-metals reacted to form a covalent
  compound
• The reaction was both
• Burning occurred without oxygen as long as
  another oxidizing agent is present

a combination reaction
a redox reaction
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Comments

• Although the element phosphorus
• is essential for life its elemental form is
  highly reactive and poisonous
• White phosphorus is stored under water to prevent
  it from reacting with oxygen in the air
• Red phosphorus is found in matches and is
  relatively air stable compared to white phosphorus