Question

to check the ions present in toothpaste and determine the quality-project

Answer 1

Every toothpaste contains the ingredients like binders, abrasives, subsers, humectants, flavors, sweeteners, fluorides, tooth whiteners, preservatives, and water. There are different tests performed to test the different cations and anions present in a toothpaste.

1. Presence of Carbonate (CO₃) - Take a part of the toothpaste solution and add MgSO₄ solution. Formation of white precipitate indicates the presence of carbonate. CO₃ + MgSO₄ → MgCO₃ + SO₄ (white ppt.).

2. Calcium - Take a part of the toothpaste solution and add Ammonium hydroxide (NH₄OH) solution. Formation of white precipitate indicates the presence of calcium.

3. Phosphate - Take a part of the toothpaste solution and add magnesium mixture of Ammonium hydroxide (NH₄OH) and Ammonium chloride (NH₄Cl) solution. Formation of white precipitate indicates the presence of phosphate (PO₄).

4. Iodine - Acidify a small portion of aqueous toothpaste solution with dilute HNO₃. Boil and cool and add AgNO₃. Formation of a yellow precipitate which is insoluble in NH₄OH confirms the presence of Iodine (I).
 I + AgNO₃ → NO₃ + AgI (yellow ppt.)

5. Magnesium - Take a part of the toothpaste solution and add solid Ammonium chloride (NH₄Cl) and Ammonium hydroxide (NH₄OH) in slight excess. Then add Ammonium phosphate. Formation of white precipitate indicates the presence of Magnesium.
MgCl₂ + NH₄OH+ (NH₃)₂HPO₄ → Mg(NH₄)PO₄ + 2NH₄ +H₂O.