氢氧化钠法测定盐酸
AN-T-236
2023-09
zh
Fast and reliable potentiometric titration of HCl with NaOH
盐酸是一种强无机矿酸，在化学工业中具有重要意义。盐酸与氢氧化钠的电位滴定是实验室中非常重要也是非常常见的分析之一。本应用说明介绍了一种酸碱滴定法，使用带有集成 Pt1000 温度传感器的 pH 电极，用 NaOH 测定盐酸的浓度，以获得非常准确的结果。
Hydrochloric acid (HCl) is a strong inorganic acid also classified as a mineral acid. HCl is an essential solution with great significance in the chemical industry. Among other things, it is used in the processing of ores, serves as a cleaning agent, or is used during metal processing for pickling, etching, and soldering. Hydrochloric acid is also an important standard solution in the pharmaceutical industry.
The potentiometric titration of hydrochloric acid with sodium hydroxide is one of the most important and also most frequent analyses performed in the laboratory. Titration is best suited for this purpose. The method is very accurate, inexpensive, and fast.
In this Application Note, an acid-base titration is presented where the concentration of HCl is determined with sodium hydroxide (NaOH) using a pH electrode with an integrated Pt1000 temperature senor for the most accurate results.
This application is demonstrated on c(HCl) = 1 mol/L. Sample preparation is not required.
The determinations are carried out on an Eco Titrator equipped with a Unitrode with integrated Pt1000 (Figure 1). The acidic HCl reacts with a basic solution of NaOH via the following neutralization reaction mechanism:
HCl + NaOH → NaCl + H2O
An appropriate amount of sample is pipetted into the titration beaker, then deionized water is added. Afterwards, the solution is titrated until after the first endpoint with standardized sodium hydroxide.
This method offers very accurate results, as displayed in Table 1. One exemplary titration curve of HCl is shown in Figure 2.
Table 1. Results of the potentiometric titration of HCl (n = 10).
| Sample (n = 10) | NaOH in mL | HCl in mol/L | Recovery in % |
|---|---|---|---|
| Mean value | 4.994 | 0.999 | 100.00 |
| SD(abs) | 0.00 | 0.00 | 0.05 |
| SD(rel) in % | 0.05 | 0.05 | 0.05 |
HCl titration with NaOH is one of the absolute methods of routine laboratory analysis.
The compact Eco Titrator with integrated magnetic stirrer and touch-sensitive user interface is ideal for this kind of acid-base titration. The system is user-friendly and cost-effective. Pre-installed methods on the Eco Titrator make it easy for customers without laboratory experience to get started creating precise, fast, reliable, and GLP-compliant results. With a small footprint (approximately DIN A4), the Eco Titrator is suitable for laboratories even with space limitations.
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