Question

Describe identification procedure of Ba2+ or Ca2+ radical from given unknown solution.

Answer 1

Answer:

There are 3 steps involve in this procedure :

Step 1: treat the mixture with 'NH₄Cl + NH₄OH ‘and (NH₄)₂ CO₃.

Step 2: take 2 parts of the mixture and mix it together with CH₃COOH (acetic acid)

Step 3: now, you should treat one part with ammonium oxalate solution (NH₄)₂C₂O₄ and the other part with Potassium chromate (K₂CrO₄) solution

From result given, you can observe that when added with potassium chromate it gives a yellow precipitate for barium and when added with ammonium oxalate solution, it gives a white test tube for calcium.  

Answer 2

Identification procedure of Ba2+ and Ca2+ radical from given unknown solution is given below:--

1. Since both  Ba2+ and Ca2+ belong to fifth group so they have same procedure till their group identification but their presence in the solution is confirmed by their confirmatory test.
2. First add dilute sulphuric acid to the unknown solution as no precipitate is formed so 1st group is absent.
3. Now pass H2S gas in above sample again there is no precipitation so second group is also absent.
4. For third group remove H2S gas and add ammonium chloride and add excess of ammonium hydroxide again no precipitate so third group is also absent.
5. Again pass H2S gas in solution as again there will be no precipitation so 4th group also absent.
6. Heat the sample and add ammonium carbonate a white precipitate is formed which confirms the presence of 5th group so the ions are may be Ba2+ or Ca2+.
7. To confirm barium we dissolve the precipitate in dilute acetic acid  and add potassium chromate solution drop wise yellow precipitate confirms presence of Ba2+ ion and on flame we get grassy green colour .
8. To confirm Ca2+ we dissolve the solution in acetic acid and to it add ammonium oxalate and ammonium hydroxide a white precipitate is formed confirming presence of calcium ions and on flame we get red flame.