pH 적정 곡선

pH 미터로 완전한 산염기 적정 곡선 작성하기

Titrations Intermediate (High School) 50 분 ~$15.00

목표

산염기 적정 중 pH 값을 기록하고, 당량점과 완충 영역을 나타내는 완전한 S자 형태의 적정 곡선을 작성한다.

배경

A pH titration curve provides far more information than an indicator-based titration. The S-shaped curve reveals the buffer region, half-equivalence point (where pH equals pKa for weak acids), and the sharpness of the equivalence point. This experiment compares the curves of strong and weak acids.

안전 경고

  • HCl and NaOH are corrosive
  • Wear safety goggles and gloves
  • Handle the pH electrode carefully — it is fragile

필수 개인 보호 장비

goggles gloves lab_coat

재료

  • Hydrochloric acid (HCl) (50 mL)
    0.1M
  • Sodium hydroxide (NaOH) (100 mL)
    0.1M
  • pH buffer solutions (3 bottles)
    pH 4, 7, 10 for calibration
  • Distilled water (200 mL)

장비

50 mL burette Burette stand and clamp 250 mL beaker pH meter with electrode Magnetic stirrer 25 mL pipette Graph paper

실험 절차

1

Calibrate the pH meter using the three buffer solutions (pH 4, 7, 10).

5 분 Handle pH electrode gently
2

Pipette 25.0 mL of 0.1M HCl into the beaker. Record the initial pH.

3 분
3

Fill the burette with 0.1M NaOH. Record the initial volume.

3 분
4

Add NaOH in 1.0 mL increments, recording the pH after each addition. When pH changes rapidly, switch to 0.2 mL increments.

25 분
5

Continue adding NaOH until the pH is above 12. Add a few more points past the equivalence point.

5 분
6

Plot pH (y-axis) versus volume of NaOH (x-axis) to construct the titration curve.

7 분

예상 결과

The curve should show a characteristic S-shape: slowly rising pH initially, a steep jump around the equivalence point (pH 7 for strong acid-strong base), then leveling off at high pH. The equivalence point volume should be approximately 25 mL.

정리

Rinse the pH electrode and store in storage solution. Neutralize waste before disposal. Rinse all glassware.

세부 정보

카테고리
Titrations
난이도
Intermediate (High School)
소요 시간
50 분
예상 비용
$15.00
단계
6
재료
4

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Frequently Asked Questions

What is the objective of pH 적정 곡선?
산염기 적정 중 pH 값을 기록하고, 당량점과 완충 영역을 나타내는 완전한 S자 형태의 적정 곡선을 작성한다.
How difficult is pH 적정 곡선?
This experiment is rated as Intermediate (High School). It takes approximately 50 minutes to complete.
What safety precautions are needed for pH 적정 곡선?
Key safety precautions include: HCl and NaOH are corrosive; Wear safety goggles and gloves; Handle the pH electrode carefully — it is fragile.
What materials are needed for pH 적정 곡선?
The main materials required are: Hydrochloric acid (HCl), Sodium hydroxide (NaOH), pH buffer solutions, Distilled water.
What results should I expect from pH 적정 곡선?
The curve should show a characteristic S-shape: slowly rising pH initially, a steep jump around the equivalence point (pH 7 for strong acid-strong base), then leveling off at high pH. The equivalence point volume should be approximately 25 mL.