pH滴定曲线

用pH计绘制完整的酸碱滴定曲线

Titrations Intermediate (High School) 50 分钟 ~$15.00

目标

记录酸碱滴定过程中的pH值，构建显示当量点和缓冲区域的完整S形滴定曲线。

背景

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.

安全警告

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

所需PPE

goggles gloves lab_coat

材料

  • 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)

设备

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

步骤

1

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

5 分钟 Handle pH electrode gently
2

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

3 分钟
3

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

3 分钟
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 分钟
5

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

5 分钟
6

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

7 分钟

预期结果

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.

清理

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

详情

类别
Titrations
难度
Intermediate (High School)
时长
50 分钟
预估费用
$15.00
步骤数
6
材料
4

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Frequently Asked Questions

What is the objective of pH滴定曲线?
记录酸碱滴定过程中的pH值，构建显示当量点和缓冲区域的完整S形滴定曲线。
How difficult is pH滴定曲线?
This experiment is rated as Intermediate (High School). It takes approximately 50 minutes to complete.
What safety precautions are needed for pH滴定曲线?
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滴定曲线?
The main materials required are: Hydrochloric acid (HCl), Sodium hydroxide (NaOH), pH buffer solutions, Distilled water.
What results should I expect from pH滴定曲线?
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.