Elemental phosphorus gives PH_3 and Na^+""^(-)P(OH)_2 upon basic hydrolysis. How is the reaction formulated?

1 Answer
May 25, 2017

This is disproportionation............elemental phosphorus is simultaneously reduced and oxidized.......

Explanation:

"Reduction half equation"

1/4P_4 +3H_2O(l) + 3e^(-) rarr PH_3(g)+3HO^(-) (i)

"Oxidation half equation"

1/4P_4 + 2HO^(-)rarr ""^(-)stackrel(+I)P(OH)_2+e^(-) (ii)

And we take (i) + 3xx(ii) to eliminate the electrons which are conceptual particles..........

P_4 + 3HO^(-)+3H_2O(l) rarr PH_3(g) + 3(HO)_2P^(-)

Which (I think!) is balanced with respect to mass and charge, as indeed it must be if we purport to represent chemical reality.