Testing for Silver ion | Qualitative Analysis of Ag+

In qualitative analysis, there are testing to identify Ag+ ion from other cations. Silver ion form soluble compounds, insoluble compounds, complex ions in water. Those characteristics are used to to test occurrence of Ag+ ion. AgCl, AgBr, AgI are famous insoluble compounds.

In this tutorial, we will learn followings of silver ion.

  1. Tests for Ag+ ion under qualitative analysis reactions and physical observations
  2. Problems of identifying Ag+ ion from other cations

Testing for Ag+ ion

  1. Aqueous Ag+ and ammonia solution
  2. Addition of dilute HCl to aqueous Ag+ ion solution
  3. Aqueous potassium chromate and Ag+ reaction
  4. With Br- ion and I- ion

Testing Ag+ ion by aqueous ammonia solution

This experiment includes several steps. First, add aqueous ammonia to Ag+ ion solution. It will give AgOH. But AgOH immediately decomposes to Ag2O (Silver oxide) which is a black brown precipitate.

Then, add more ammonia to solution which contains silver oxide precipitate. You can see black brown precipitate dissolve and form colourless solutions.

Ag+ + NH3 = Ag(NH3)2 complex ion

Addition of dilute HCl to aqueous Ag+ ion solution

Addition of dilute HCl gives a white precipitate of AgCl. AgCl is not soluble in water. This precipitate will dissolve in an excess of concentrated HCl acid and form colourless solution.

Also, that AgCl white precipitate is soluble in excess ammonia solution. It forms a colourless solution.

AgCl is soluble in HCl

Add aqueous potassium chromate to aqueous Ag+ ion

When aqueous potassium chromate (K2CrO4) solution to aqueous Ag+ ion solution. Abricked red precipitate is given. This precipitate is silver chromate (Ag2CrO4).

silver ion and potassium dichromate

With bromide ions and iodide ions

Silver bromide is a pale-yellow colour compound and insoluble in water.

Also, silver iodide is a yellow, water insoluble compound.

Questions asked by students