Question

Complete the following reaction

${\mathrm{P}}_4+\mathrm{NaOH}+{\mathrm{H}}_2\mathrm{O}\to$

Write the balanced equation.

Answer 1

• It is a disproportionation reaction as ${\mathrm{P}}_4$ undergoes both oxidation and reduction.
• The oxidation state of P in P₄ is 0, it becomes -3 in PH₃ i.e. reduced, and becomes +1 in NaH₂PO₂ i.e. oxidised.
• Phosphorous$\left({\mathrm{P}}_4\right)$ reacts with Sodium hydroxide$\left(\mathrm{NaOH}\right)$ and water to give Sodium hypophosphite$\left({\mathrm{NaH}}_2{\mathrm{PO}}_2\right)$ and Phosphine$\left({\mathrm{PH}}_3\right)$.
• ${\mathrm{P}}_4+3\mathrm{NaOH}+3{\mathrm{H}}_2\mathrm{O}\to 3{\mathrm{NaH}}_2{\mathrm{PO}}_2+{\mathrm{PH}}_3$