Chuẩn Độ Axit-Bazơ với Metyl Da Cam

Chuẩn độ bazơ yếu bằng axit mạnh

Titrations Intermediate (High School) 40 phút ~$12,00

Mục tiêu

Xác định nồng độ dung dịch natri cacbonat bằng cách chuẩn độ với axit clohydric dùng metyl da cam làm chỉ thị, phù hợp cho điểm tương đương axit.

Bối cảnh

Methyl orange changes color at pH 3.1-4.4 (red to yellow), making it suitable for titrations where the equivalence point is in the acidic range. Sodium carbonate reacts with HCl in a two-step process: first forming NaHCO₃, then NaCl + H₂O + CO₂. Methyl orange detects the second equivalence point.

Cảnh báo an toàn

  • HCl is corrosive — avoid skin contact
  • Wear safety goggles throughout
  • Methyl orange is an azo dye — avoid contact with skin

PPE cần thiết

goggles lab_coat

Vật liệu

  • Sodium carbonate (Na₂CO₃) (100 mL)
    Unknown concentration
  • Hydrochloric acid (HCl) (100 mL)
    0.1M standardized
  • Methyl orange indicator (5 mL)
    0.1% solution
  • Distilled water (200 mL)

Thiết bị

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

Quy trình

1

Rinse the burette with HCl solution, then fill it to the 0 mL mark.

3 phút
2

Pipette 25.0 mL of sodium carbonate solution into the Erlenmeyer flask.

2 phút
3

Add 2-3 drops of methyl orange indicator. The solution should appear yellow (alkaline).

1 phút
4

Add HCl slowly while swirling. Watch for the color change from yellow through orange.

8 phút
5

Near the endpoint, add drop by drop until the solution changes from yellow to a persistent orange/salmon color.

5 phút
6

Record the volume of HCl used. Repeat for concordant results.

15 phút
7

Calculate the concentration of Na₂CO₃ considering the 1:2 stoichiometry (Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂).

5 phút

Kết quả dự kiến

The endpoint shows a clear transition from yellow to a persistent orange/salmon color. The volume ratio should confirm the 1:2 molar ratio of carbonate to acid.

Dọn dẹp

Neutralize waste solutions. Rinse all glassware with distilled water. Drain and rinse the burette.

Frequently Asked Questions

What is the objective of Chuẩn Độ Axit-Bazơ với Metyl Da Cam?
Xác định nồng độ dung dịch natri cacbonat bằng cách chuẩn độ với axit clohydric dùng metyl da cam làm chỉ thị, phù hợp cho điểm tương đương axit.
How difficult is Chuẩn Độ Axit-Bazơ với Metyl Da Cam?
This experiment is rated as Intermediate (High School). It takes approximately 40 minutes to complete.
What safety precautions are needed for Chuẩn Độ Axit-Bazơ với Metyl Da Cam?
Key safety precautions include: HCl is corrosive — avoid skin contact; Wear safety goggles throughout; Methyl orange is an azo dye — avoid contact with skin.
What materials are needed for Chuẩn Độ Axit-Bazơ với Metyl Da Cam?
The main materials required are: Sodium carbonate (Na₂CO₃), Hydrochloric acid (HCl), Methyl orange indicator, Distilled water.
What results should I expect from Chuẩn Độ Axit-Bazơ với Metyl Da Cam?
The endpoint shows a clear transition from yellow to a persistent orange/salmon color. The volume ratio should confirm the 1:2 molar ratio of carbonate to acid.