Question

Identify the salts P from the observation given below:

On performing the flame test salt P produces a lilac-colored flame and its solution gives a white precipitate with silver nitrate solution, which is soluble in ammonium hydroxide solution.

Answer 1

• Double displacement reaction: Double displacement reactions are those in which two compounds in a solution react to form two new compounds by mutual exchange of radicals.
• Precipitation reaction: Precipitation reactions are usually double displacement reactions involving the production of a solid form residue called the precipitate.

About the flame test:

• On performing the flame test salt P produces a lilac-colored flame. This test indicates the presence of Potassium salt $\left(\mathrm{KCl}\right)$.
• The chemical reaction between potassium chloride $\left(\mathrm{KCl}\right)$ and Silver nitrate $\left({\mathrm{AgNO}}_3\right)$, in which solid silver chloride $\left(\mathrm{AgCl}\right)$ is precipitated out. This indicates the presence of chloride ions $\left({\mathrm{Cl}}^{-}\right)$
• The chemical is as follows.

$\underset{\mathrm{Silver}\mathrm{nitrate}}{\mathrm{Ag}\left({\mathrm{NO}}_3\right)\left(\mathrm{s}\right)}+\underset{\mathrm{Potassium}\mathrm{chloride}}{\mathrm{KCl}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Silver}\mathrm{chloride}}{\mathrm{AgCl}\left(\mathrm{s}\right)}+\underset{\mathrm{Potassium}\mathrm{nitrate}}{{\mathrm{KNO}}_3\left(\mathrm{aq}\right)}$

• The formed Silver chloride is going to be soluble in ammonium hydroxide solution.

Therefore the compound P is Potassium chloride.