test for barium(Ba2+) ion salt analysis class 11th and 12th practical #saltanalysis

Summary

This video explains the process of performing a barium test in chemistry, focusing on the identification of barium salts through various group analysis techniques. The presenter outlines step-by-step procedures for detecting different groups, including Group 1 to Group 5, using reagents like HCl, H2S, ammonium salts, and potassium chromate. The key steps for confirming barium presence through reactions such as the formation of yellow precipitates with potassium chromate and white precipitates with H2SO4 are demonstrated. The video aims to simplify the process, making it accessible for practical exams and learning.

Takeaways

• 😀 The video explains the barium test and its significance in salt analysis.
• 😀 It describes the process of preparing a solution (OS) by dissolving the barium salt in water.
• 😀 The first step in testing is to use hydrochloric acid (HCl) to check for a white precipitate, which indicates the presence of group one cations.
• 😀 If no white precipitate forms, the test proceeds by passing H2S gas to check for group two cations (like barium).
• 😀 A black precipitate after H2S gas indicates the presence of group two cations, specifically barium.
• 😀 The video highlights the importance of using specific reagents like ammonium chloride (NH4Cl) and ammonium hydroxide (NH4OH) to test for group three cations.
• 😀 The presence of a white gelatinous precipitate with NH4Cl and NH4OH confirms the presence of group three cations.
• 😀 The test for group four cations requires the use of ammonium chloride (NH4Cl), ammonium hydroxide (NH4OH), and H2S gas to detect any black, white, or buff precipitates.
• 😀 The formation of a white precipitate when ammonium carbonate (NH4)2CO3 is added confirms the presence of group five cations, including barium.
• 😀 The confirmation of barium is done by adding potassium chromate (K2CrO4) to the solution. A yellow precipitate indicates the presence of barium chromate, confirming barium’s presence.
• 😀 The video concludes with a suggestion to review other related chemistry and salt analysis videos to perform well in board practical exams.

Q & A

What is the primary focus of the experiment described in the video?

The experiment focuses on performing a barium test in salt analysis, specifically identifying the presence of barium among other elements like calcium and strontium in a sample.

What is the first step in the barium test for salt analysis?

The first step is to create an 'O.S.' (Original Solution) by dissolving the salt in water, ensuring it is well mixed.

Why is hydrochloric acid (HCl) added to the solution in the barium test?

Hydrochloric acid is added to the solution to check for the formation of a white precipitate, which indicates the presence of Group 1 cations in the salt sample.

What does the presence of a white precipitate after adding HCl indicate?

The formation of a white precipitate after adding HCl indicates the presence of Group 1 cations, confirming that they are present in the solution.

What is the role of hydrogen sulfide (H2S) in this experiment?

Hydrogen sulfide (H2S) is passed through the solution to test for the presence of Group 2 cations. If a black precipitate forms, it indicates the presence of Group 2 cations, like lead or copper.

How can you confirm the presence of Group 3 cations in the sample?

To confirm the presence of Group 3 cations, ammonium chloride (NH4Cl) and ammonium hydroxide (NH4OH) are added. If a white gelatinous precipitate forms, Group 3 cations are present.

What is the significance of using ammonium carbonate (NH4)2CO3 in the barium test?

Ammonium carbonate (NH4)2CO3 is used to precipitate out certain cations, including barium. The formation of a white precipitate upon adding ammonium carbonate confirms the presence of Group 5 elements like calcium, strontium, or barium.

Why is acetic acid heated before adding the precipitate?

Acetic acid is heated to help dissolve the white precipitate. This ensures that the subsequent tests for identifying barium are accurate and effective.

What is the purpose of adding potassium chromate (K2CrO4) to the solution?

Potassium chromate is added to the solution to check for the formation of a yellow precipitate, which would confirm the presence of barium as barium chromate.

How is the presence of barium finally confirmed in the experiment?

The presence of barium is confirmed by adding potassium chromate to the solution. If a yellow precipitate forms, it indicates the presence of barium as barium chromate. Additionally, adding diluted sulfuric acid (H2SO4) can also confirm the presence of barium by producing a white precipitate of barium sulfate.