過マンガン酸カリウムによる酸化還元滴定

KMnO₄を使った鉄(II)濃度の決定

Titrations Advanced (University) 50 分 ~$18.00

目的

自己指示薬である標準過マンガン酸カリウム溶液で硫酸鉄(II)溶液を滴定し、その濃度を決定する。

背景

Potassium permanganate is a powerful oxidizing agent that reacts with Fe2+ in acidic solution. MnO4- (purple) is reduced to Mn2+ (nearly colorless), so permanganate acts as its own indicator. The endpoint occurs when a single drop of excess KMnO4 produces a permanent pink/purple color.

安全上の警告

  • KMnO₄ stains skin and clothing permanently
  • H₂SO₄ is corrosive
  • Wear safety goggles and gloves throughout
  • Wipe up KMnO₄ spills immediately

必要なPPE

goggles gloves lab_coat

材料

  • Iron(II) sulfate solution (100 mL)
    Unknown concentration
  • Potassium permanganate (KMnO₄) (100 mL)
    0.02M standardized
  • Sulfuric acid (H₂SO₄) (50 mL)
    1M
  • Distilled water (200 mL)

器具

50 mL burette Burette stand and clamp 250 mL Erlenmeyer flask 25 mL pipette Pipette filler White tile

手順

1

Rinse the burette with KMnO₄ solution, then fill to the 0 mL mark. Record the meniscus reading (read from the top of the meniscus since KMnO₄ is opaque).

5 分 KMnO₄ stains — handle carefully
2

Pipette exactly 25.0 mL of iron(II) sulfate solution into the Erlenmeyer flask.

3 分
3

Add 10 mL of 1M sulfuric acid to the flask to ensure acidic conditions.

2 分 Handle acid carefully
4

Slowly add KMnO₄ from the burette while swirling. Each drop will decolorize as Fe2+ reduces MnO4-.

10 分
5

As the endpoint approaches, add drop by drop until a faint permanent pink/purple color persists for 30 seconds.

5 分
6

Record the final burette reading and calculate the volume used.

2 分
7

Repeat at least twice for concordant results.

15 分
8

Calculate the Fe2+ concentration using the balanced equation: MnO4- + 5Fe2+ + 8H+ → Mn2+ + 5Fe3+ + 4H2O.

5 分

予想される結果

The solution should transition from colorless to a persistent faint pink/purple at the endpoint. The 1:5 molar ratio of KMnO₄ to Fe2+ should yield an accurate concentration.

後片付け

Dilute waste solutions and dispose of KMnO₄ waste according to lab protocols. Rinse the burette thoroughly with water. Clean any stains with dilute acid or sodium sulfite.

詳細

カテゴリ
Titrations
難易度
Advanced (University)
所要時間
50 分
推定費用
$18.00
ステップ数
8
材料
4

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Frequently Asked Questions

What is the objective of 過マンガン酸カリウムによる酸化還元滴定?
自己指示薬である標準過マンガン酸カリウム溶液で硫酸鉄(II)溶液を滴定し、その濃度を決定する。
How difficult is 過マンガン酸カリウムによる酸化還元滴定?
This experiment is rated as Advanced (University). It takes approximately 50 minutes to complete.
What safety precautions are needed for 過マンガン酸カリウムによる酸化還元滴定?
Key safety precautions include: KMnO₄ stains skin and clothing permanently; H₂SO₄ is corrosive; Wear safety goggles and gloves throughout.
What materials are needed for 過マンガン酸カリウムによる酸化還元滴定?
The main materials required are: Iron(II) sulfate solution, Potassium permanganate (KMnO₄), Sulfuric acid (H₂SO₄), Distilled water.
What results should I expect from 過マンガン酸カリウムによる酸化還元滴定?
The solution should transition from colorless to a persistent faint pink/purple at the endpoint. The 1:5 molar ratio of KMnO₄ to Fe2+ should yield an accurate concentration.