Question

What reagent used for testing fluoride Ion in water?
A. Alizarin-S
B. Quinalizarin
C. Phenolphthalein
D. Benzene

Answer 1

Hint: In this question we have to find the reagent which is used for testing the fluoride ion which is present in the water molecules. As for we easily test the above given option to find the correct reagent from the above options after which we test the fluoride ion from the water molecule.

Complete step-by-step answer:Before starting a solution to this,
we see some major properties of fluoride by which we can easily solve this question, So, The atomic number of fluoride is $9$ . The melting point and boiling point of fluorine is $ - {219.6^ \circ }C$ and $ - {188^ \circ }C$.
Additionally, it is the most lightweight member of the halogen group and the most reactive element that is present. It is also the periodic table's most electronegative element.
Let's learn more about testing for fluoride ions in the water today.
We are aware that the fluoride ion is easily recognised by the way fluoride reacts with zirconium alizarin-s dye. If fluoride is found in the solution, it transforms into a colourless zirconium fluoride material.
The easily measured element F is created when the fluoride ion interacts with the zirconium alizarin-S colour. F reacts with zirconium to form colourless zirconium fluoride. The dye loses colour intensity as the fluoride level increases.
Therefore, the correct answer is Alizarin-S.
Hence, the correct option is (A).

Note: Here in this question, we just talk about Alizarin-S. Now we just know about it and what its uses are. Alizarin-S is an organic salt of sodium which contains $3,4 - dihydroxy - 9,10 - dioxo - 9,10 - dihydroanthracene - 2 - sulfonate$ And it is used as a red dye and reagent in many reactions.