Question

Reagent used to test phosphate ion is:
A.Nessler’s reagent
B.Ammonium molybdate
C.Baeyer’s reagent
D.Fenton’s reagent

Answer 1

Hint: Reagent is basically a substance or mixture which is used for the chemical analysis or various chemical reactions. To solve this question, we need to know about the phosphate ion, its properties and its various chemical reactions.

Complete step by step answer:
Phosphate also known as phosphate ion is a trivalent inorganic anion and a conjugate base of hydrogen phosphate. Its chemical formula is $(P{O_4}^{3-})$. It is composed of a group of salts containing the phosphate ion, the dihydrogen phosphate ion or the hydrogen phosphate ion and positive charged ions such as calcium or sodium.
Now, let’s discuss reagents. A reagent is a substance or compound added to a system to cause a chemical reaction or is added to the test if a reaction occurs. Some of the examples of reagents are Fenton’s reagent, Grignard reagents and many more. Now, the reagent that is used to test phosphate ion is Ammonium molybdate. Now, in the qualitative method, a small amount of the sample is acidified with concentrated nitric acid and a little ammonium molybdate i.e. the reagent is added. So, the presence of phosphate ions is indicated by the formation of a bright yellow precipitate layer of ammonium phosphomolybdate. This test is also used to detect arsenic.
Therefore, ammonium molybdate is used to test phosphate ion.

Hence, option B is correct.

Note: Phosphorous is especially noted for its function in absorbing and transforming energy from the sun into useful compounds for plants. Moreover, it is used in toothpaste as a polishing agent, in pharmaceuticals, in fire extinguishers and many more.