Chuẩn Độ Ngược Viên Kháng Axit

Đo khả năng trung hòa axit của thuốc kháng axit thương mại

Titrations Intermediate (High School) 60 phút ~$12,00

Mục tiêu

Xác định khả năng trung hòa axit của viên thuốc kháng axit thương mại bằng phương pháp chuẩn độ ngược.

Bối cảnh

Direct titration of antacid is impractical because the active ingredients dissolve slowly. In a back titration, excess acid is added to the antacid, allowed to react fully, and the remaining unreacted acid is titrated with base. The difference reveals how much acid the antacid neutralized.

Cảnh báo an toàn

  • HCl and NaOH are corrosive
  • Wear safety goggles and gloves
  • Use caution with the hot plate

PPE cần thiết

goggles gloves lab_coat

Vật liệu

  • Antacid tablets (2 tablets)
    CaCO₃-based, like Tums
  • Hydrochloric acid (HCl) (200 mL)
    0.5M
  • Sodium hydroxide (NaOH) (100 mL)
    0.5M standardized
  • Phenolphthalein indicator (5 mL)
  • Distilled water (200 mL)

Thiết bị

50 mL burette Burette stand and clamp 250 mL Erlenmeyer flask 25 mL pipette Mortar and pestle Analytical balance Hot plate

Quy trình

1

Weigh the antacid tablet accurately on the analytical balance and record the mass.

3 phút
2

Crush the tablet into a fine powder using the mortar and pestle.

3 phút
3

Transfer the powder to the Erlenmeyer flask. Add exactly 50.0 mL of 0.5M HCl using the pipette.

3 phút Handle HCl carefully
4

Gently heat the mixture on the hot plate for 10 minutes to ensure complete reaction of the antacid.

12 phút Do not boil vigorously
5

Allow the solution to cool to room temperature.

5 phút
6

Add 2-3 drops of phenolphthalein indicator.

1 phút
7

Fill the burette with 0.5M NaOH. Titrate the excess HCl until a persistent pale pink color appears.

10 phút
8

Record the volume of NaOH used. Calculate moles of excess HCl, then moles neutralized by the antacid.

5 phút

Kết quả dự kiến

A typical CaCO₃-based antacid tablet (500 mg) should neutralize approximately 10 mmol of HCl. The mass of CaCO₃ calculated should approximate the labeled amount on the package.

Dọn dẹp

Neutralize all waste solutions before disposal. Rinse glassware thoroughly. Clean the mortar and pestle.

Frequently Asked Questions

What is the objective of Chuẩn Độ Ngược Viên Kháng Axit?
Xác định khả năng trung hòa axit của viên thuốc kháng axit thương mại bằng phương pháp chuẩn độ ngược.
How difficult is Chuẩn Độ Ngược Viên Kháng Axit?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for Chuẩn Độ Ngược Viên Kháng Axit?
Key safety precautions include: HCl and NaOH are corrosive; Wear safety goggles and gloves; Use caution with the hot plate.
What materials are needed for Chuẩn Độ Ngược Viên Kháng Axit?
The main materials required are: Antacid tablets, Hydrochloric acid (HCl), Sodium hydroxide (NaOH), Phenolphthalein indicator, Distilled water.
What results should I expect from Chuẩn Độ Ngược Viên Kháng Axit?
A typical CaCO₃-based antacid tablet (500 mg) should neutralize approximately 10 mmol of HCl. The mass of CaCO₃ calculated should approximate the labeled amount on the package.