Detection of Phosphorus

Rarely Tested

  • Step 1: Fusion to Phosphate


    $$\text{Na}_2\text{O}_2 + \text{P} \xrightarrow{\Delta} \text{Na}_3\text{PO}_4$$

  • Step 2: Acidification to Phosphoric Acid


    $$\text{Na}_3\text{PO}_4 + 3\text{HNO}_3 \to \text{H}_3\text{PO}_4 + 3\text{NaNO}_3$$

  • Step 3: Reaction with Ammonium Molybdate


    $$\text{H}_3\text{PO}_4 + 12(\text{NH}_4)_2\text{MoO}_4 + 21\text{HNO}_3 \to (\text{NH}_4)_3\text{PO}_4 \cdot 12\text{MoO}_3 \downarrow \text{ (Canary Yellow)} + 21\text{NH}_4\text{NO}_3 + 12\text{H}_2\text{O}$$

    • Result: Canary Yellow precipitate of Ammonium Phosphomolybdate ($$(\text{NH}_4)_3\text{PO}_4 \cdot 12\text{MoO}_3$$) confirms Phosphorus.

    No related questions available for this formula yet.

    Go back to topics

    Join CAT 2026 course by 5-Time CAT 100%iler

    Start your IIM journey with the right preparation and crack CAT 2026.

    Enroll Now