Easy MCQ +4 / -1 PYQ · JEE Mains 2024

In qualitative test for identification of presence of phosphorous, the compound is heated with an oxidising agent. Which is further treated with nitric acid and ammonium molybdate respectively. The yellow coloured precipitate obtained is :

  1. A $\mathrm{Na}_3 \mathrm{PO}_4 \cdot 12 \mathrm{MoO}_3$
  2. B $$\left(\mathrm{NH}_4\right)_3 \mathrm{PO}_4 \cdot 12\left(\mathrm{NH}_4\right)_2 \mathrm{MoO}_4$$
  3. C $\mathrm{MoPO}_4 \cdot 21 \mathrm{NH}_4 \mathrm{NO}_3$
  4. D $\left(\mathrm{NH}_4\right)_3 \mathrm{PO}_4 \cdot 12 \mathrm{MoO}_3$ Correct answer

Solution

<p>For test of phosphorus:</p> <p>$$\mathrm{{H_3}P{O_4} + 12{(N{H_4})_2}Mo{O_4} + 21HN{O_3} \to \mathop {{{(N{H_4})}_3}\,.\,12Mo{O_3}}\limits_{(Yellow\,ppt)} + 21N{H_4}N{O_3} + 12{H_2}O}$$</p>

About this question

Subject: Chemistry · Chapter: p-Block Elements · Topic: Group 13: Boron Family

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