Question

What happens when white phosphorus is heated with concentrated $\mathrm{NaOH}$ solution in an inert atmosphere of ${\mathrm{CO}}_2$?

Answer 1

White Phosphorus

• White phosphorus is one of the allotropic forms of phosphorus.
• White phosphorous $\left({\mathrm{P}}_4\right)$ also known as tetraphosphorus and occurs from phosphate rocks. It is poisonous in nature.
• It also shows the property of chemiluminescence (glows in dark ).

Reaction of Phosphorus

• When white phosphorus $\left({\mathrm{P}}_4\right)$ is heated with concentrated sodium hydroxide solution in the presence of carbon dioxide, it gives phosphine $\left({\mathrm{PH}}_3\right)$ and sodium hypophosphite $\left({\mathrm{NaH}}_2{\mathrm{PO}}_2\right)$ as the products.
• Phosphine is highly inflammable in the air. So, in the laboratory white phosphorus is heated with concentrated $\mathrm{NaOH}$ solution in an inert atmosphere of ${\mathrm{CO}}_2$.
• The reaction is as follows,
• ${\mathrm{P}}_4\left(\mathrm{s}\right)+3\mathrm{NaOH}\left(\mathrm{aq}\right)+3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\stackrel{\mathrm{heat}\mathrm{with}\mathrm{NaOH}(\mathrm{conc}.),{\mathrm{CO}}_2}{\to }{\mathrm{PH}}_3\left(\mathrm{g}\right)+3{\mathrm{NaH}}_2{\mathrm{PO}}_2\left(\mathrm{aq}\right)$