NH4 flame test is a common chemical analysis method and one of the conventional methods for analyzing inorganic compound. It mainly excites substances through thermodynamic reactions, resulting in emission spectra within a specific wavelength range. NH4 ions are anions that can form salt compounds with cations in acidic solutions, such as ammonium nitrate, ammonium chloride, etc. The NH4 flame test is typically used to analyze other metal ions in solutions containing NH4 ions.
When conducting the NH4 flame test, the solution containing NH4 ions must first be dropped into the flame. The commonly used flame is a gas flame, which is sprayed out after mixing gas and oxygen, and its temperature can reach about 3000 ° C. During combustion, NH4 ions react with combustion products to undergo oxidation reactions, generating NH3 and H2O. The generated NH3 and combustion products undergo oxidation-reduction reactions, ultimately producing emission spectra. These emission spectra exhibit different colors within different wavelength ranges. As different ions produce different spectra, the type of ions contained can be determined by observing the color.
In the NH4 flame test, the spectral colors of different elements are different. For example, the spectral color of sodium salt is yellow, potassium salt is purple, iron salt is red, copper salt is green, calcium salt is orange red, and so on.
Overall, NH4 flame test is a fast and simple analytical method that can conveniently analyze solutions containing NH4 ions. Although flame testing cannot determine the chemical composition of a substance, it is still a very useful analytical method, especially widely used in preliminary analysis.