陰イオン同定試験

選択的化学反応で一般的な陰イオンを検出する

Qualitative Analysis Intermediate (High School) 60 分 ~$10.00

目的

特定の沈殿・酸分解・酸化還元試験を用いて未知の陰イオンを同定する。

背景

Anion analysis complements cation identification in classical qualitative analysis. Unlike cations, anions do not follow a single systematic separation scheme. Instead, they are identified through a series of specific tests: chloride with silver nitrate, sulfate with barium chloride, carbonate with acid, and so on. Understanding these tests reinforces knowledge of solubility rules and reaction types.

安全上の警告

  • AgNO₃ stains skin and clothing permanently
  • Use dilute acids only — concentrated acids can produce toxic gases
  • BaCl₂ is toxic if ingested
  • Dispose of silver waste in designated containers

必要なPPE

goggles gloves lab_coat

材料

  • Unknown anion solution (10 mL)
    Prepared by instructor
  • Silver nitrate (0.1M AgNO₃) (10 mL)
    For halide tests
  • Barium chloride (0.1M BaCl₂) (5 mL)
    For sulfate test
  • Dilute HNO₃ (2M) (10 mL)
    Acidification
  • Dilute H₂SO₄ (1M) (5 mL)
    For carbonate test
  • Limewater (Ca(OH)₂ solution) (10 mL)
    CO₂ detection
  • Brown ring test reagent (FeSO₄) (5 mL)
    For nitrate test

器具

Test tubes (8) Dropper pipettes Bunsen burner Delivery tube Test tube rack

手順

1

Carbonate test: Add dilute H₂SO₄ to 2 mL of unknown solution and pass any gas through limewater. A milky appearance confirms CO₃²⁻.

8 分
2

Sulfate test: Add BaCl₂ solution to 2 mL of unknown acidified with HNO₃. A white precipitate insoluble in acid confirms SO₄²⁻.

8 分
3

Chloride test: Add AgNO₃ to 2 mL of unknown acidified with HNO₃. A white curdy precipitate soluble in NH₄OH confirms Cl⁻.

8 分 AgNO₃ stains skin
4

Bromide test: Add AgNO₃ as above. A pale yellow precipitate slightly soluble in NH₄OH confirms Br⁻.

8 分
5

Iodide test: Add AgNO₃ as above. A yellow precipitate insoluble in NH₄OH confirms I⁻.

8 分
6

Nitrate test (brown ring): Layer concentrated H₂SO₄ under a mixture of unknown solution and FeSO₄. A brown ring at the junction confirms NO₃⁻.

10 分 Handle concentrated H₂SO₄ with extreme care
7

Record all observations, precipitate colors, and solubility behavior. Cross-reference results to identify the anion(s) present.

10 分

予想される結果

Each anion produces a characteristic response: carbonates effervesce with acid, sulfates give a white BaSO₄ precipitate, halides give colored AgX precipitates, and nitrates produce a brown ring.

後片付け

Collect silver-containing waste separately. Neutralize acid waste before disposal. Rinse all glassware thoroughly.

詳細

カテゴリ
Qualitative Analysis
難易度
Intermediate (High School)
所要時間
60 分
推定費用
$10.00
ステップ数
7
材料
7

その他の実験

pH指示薬の虹 45 min ハロゲンのバイルシュタイン試験 25 min 未知物質同定チャレンジ 75 min 植物色素のクロマトグラフィー 60 min 沈殿による陽イオンの同定 90 min 炎発光分光分析 60 min 炭水化物のデンプン-ヨウ素テスト 30 min 石けん液による硬水試験 40 min 金属イオンのホウ砂ビーズ試験 45 min

Frequently Asked Questions

What is the objective of 陰イオン同定試験?
特定の沈殿・酸分解・酸化還元試験を用いて未知の陰イオンを同定する。
How difficult is 陰イオン同定試験?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for 陰イオン同定試験?
Key safety precautions include: AgNO₃ stains skin and clothing permanently; Use dilute acids only — concentrated acids can produce toxic gases; BaCl₂ is toxic if ingested.
What materials are needed for 陰イオン同定試験?
The main materials required are: Unknown anion solution, Silver nitrate (0.1M AgNO₃), Barium chloride (0.1M BaCl₂), Dilute HNO₃ (2M), Dilute H₂SO₄ (1M).
What results should I expect from 陰イオン同定試験?
Each anion produces a characteristic response: carbonates effervesce with acid, sulfates give a white BaSO₄ precipitate, halides give colored AgX precipitates, and nitrates produce a brown ring.