What is a magneson reagent and explain its uses.

Hint :To answer this question, we first need to understand what is reagent. A reagent is a material or ingredient that is added to a system to either produce or test a chemical reaction. Although the phrases reactant and reagent are frequently used interchangeably, a reactant is a substance consumed during a chemical reaction.

Complete Step By Step Answer:
Magneson reagent - The Magneson reagent is a test that determines the presence of magnesium in a solution. It's an azo dye that's used as a spot test reagent and produces a blue lake when reacted with $ Mg{(OH)_2} $ in a basic solution.
This reagent's chemical formula is $ {C_{12}}{H_9}{N_3}{O_4} $ , and its chemical name is 4-(4-Nitrophenylazo) resorcinol.
Uses - Azo violet (p-nitrobenzeneazoresorcinol) is an azo compound (4-(4-nitrophenylazo) resorcinol). It's sold as a violet dye and has been used as a pH indicator in studies, showing yellow below pH 11 and violet above pH 13.
In the presence of magnesium salt in a slightly alkaline, or basic, environment, it also turns deep blue. The azo violet test can also be used to check for ammonium ions. Depending on the concentration of azo violet utilized, the color of ammonium chloride or ammonium hydroxide solution will change.

Note :
A dye is a colored material that forms a chemical bond with the substrate it is applied on. Dyes differ from pigments in that they do not bond chemically to the substrate they color. The dye is usually applied in an aqueous solution, and a mordant may be required to improve the dye's fastness on the fiber.