| Description |
White phosphorus (P4) is soft and flammable, red phosphorus
is powdery and usually non-flammable. Neither form reacts with water or
dilute acid but alkalis react to form phosphine gas. Used in fertilizers,
insecticides, metal treatment, detergents, etc Diagnostic tests:
Compounds containing phosphates (PO43-) give a green
flame test, especially after being moistened with sulfuric acid (H2SO4)
although this test may be rendered unsatisfactory due to other coloring
agents.
If a powdered sample is fused in a closed tube with metallic sodium or
magnesium and afterward moistened with water, hydrogen phosphide is given
off, recognized by its disagreeable odor.
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