Phosphine ($$\text{PH}_3$$) Preparation & Impurity

Laboratory Preparation Equation:

$$\text{P}_4 + 3\text{NaOH} + 3\text{H}_2\text{O} \xrightarrow{\text{Inert Atmosphere (CO}_2\text{)}} 3\text{NaH}_2\text{PO}_2 \text{ (Sodium Hypophosphite)} + \text{PH}_3 \uparrow$$

Spontaneous Inflammability Concept:

Pure phosphine is non-inflammable. It becomes spontaneously inflammable in air due to traces of diphosphine ($$\text{P}_2\text{H}_4$$) or white phosphorus vapor impurities.