Question

Write the balanced chemical equation of the following:
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Phosphorus reacts with Sodium Hydroxide and Water to form Phosphine gas along with Sodium Hypophosphite.

Answer 1

Actually, there are two reaction involving:

P4+3NaOH+3H2O⟶PH3+3NaH2PO2
White phosphorus react with sodium hydroxide and water to produce phosphine and sodium hypophosphite . Sodium hydroxide - cold, concentrated solution. This reaction takes place slowly. (Chemiday 1)

The O.S. of phosphorus in sodium hypophosphite is calculated in @Sayantan.G's answer.

P4+8NaOH+4H2O−→Δ4Na2HPO3+6H2
White phosphorus react with sodium hydroxide and water to produce disodium hydrogen phosphite and hydrogen. Sodium hydroxide - concentrated solution. The reaction takes place in a boiling solution.(Chemiday 2)

The O.S. of phosphorus in disodium hydrogen phosphite is:

+2⋅1+1+x+3⋅(−2)=0
x=+3

Answer 2

Hey mate here's your answer.....

P4 + NaOH + H2O = PH3 + NaH2PO2.

Balanced equation.....

P4 + 3NaOH + 3H2O = PH3 + 3NaH2PO2

Hope it Helps☺☺☺☺☺