Home

Citation: Qing Liu, Haishui Wang, Chao Chen. Physical Meanings and Applicable Conditions of pH Approximate Formulas of NaHA Solution[J]. University Chemistry, ;2023, 38(2): 260-265. doi: 10.3866/PKU.DXHX202204021 shu

Physical Meanings and Applicable Conditions of pH Approximate Formulas of NaHA Solution

1.
Analytical and Testing Center, South China University of Technology, Guangzhou 510640, China;
2.
School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China;
3.
College of Life Sciences, South China Agricultural University, Guangzhou 510642, China

Received Date: 8 April 2022

Approximate calculation of the pH of a NaHA solution plays an important role in analytical chemistry. However, the physical meanings and applicable conditions of the pH approximate formulas are not demonstrated in detail in current textbooks. In this paper, the applicable conditions and physical significance of various approximate formulas are described. The approximate formulas with incorrect physical meanings and inappropriate applicable conditions should be modified. NaHA solutions can be categorized as acidic (K_a1K_a2 > K_w) or alkaline (K_a1K_a2 <K_w). When cK_a2 ≥ 20K_w, by assuming that the production of OH^- from water and from HA^- is negligible, the approximate formula of an acidic NaHA solution is obtained. When c ≥ 20K_a1 (namely cK_b2 ≥ 20K_w), the approximate formula of an alkaline NaHA solution is obtained by ignoring the production of H⁺ from water and HA^-. The formula pH = (pK_a1 + pK_a2)/2 is suitable for both acidic and alkaline NaHA solutions, but their applicable conditions are quite different. This paper carefully discussed the pH calculation of NaHA solutions. The computation results demonstrated that some formulas should be disabled and the related wrong statements in textbooks be corrected.
- Amphiprotic substance,
- NaHA,
- pH approximate formula,
- Physical meanings,
- Applicable conditions
1. [1]
2. [2]
3. [3]
4. [4]
1. [1]
  Xiaohui Li , Ze Zhang , Jingyi Cui , Juanjuan Yin . Advanced Exploration and Practice of Teaching in the Experimental Course of Chemical Engineering Thermodynamics under the “High Order, Innovative, and Challenging” Framework. University Chemistry, 2024, 39(7): 368-376. doi: 10.3866/PKU.DXHX202311027
2. [2]
  Wenkai Chen , Yunjia Shen , Xiangmeng Kong , Yanli Zeng . Quantum Chemistry Calculation of Key Physical Quantity in Circularly Polarized Luminescence: Introducing an Exploratory Computational Chemistry Experiment. University Chemistry, 2025, 40(3): 83-91. doi: 10.12461/PKU.DXHX202405018
3. [3]
  Zhenming Xu , Mingbo Zheng , Zhenhui Liu , Duo Chen , Qingsheng Liu . Experimental Design of Project-Driven Teaching in Computational Materials Science: First-Principles Calculations of the LiFePO₄ Cathode Material for Lithium-Ion Batteries. University Chemistry, 2024, 39(4): 140-148. doi: 10.3866/PKU.DXHX202307022
4. [4]
  Suqing Shi , Anyang Li , Yuan He , Jianli Li , Xinjun Luan . Exploration and Practice of the “Progressive” Integrated Training Mode for Innovative Chemistry Talents at Comprehensive Universities in Western China. University Chemistry, 2024, 39(6): 42-49. doi: 10.3866/PKU.DXHX202402009
5. [5]
  Yujia Luo , Yunpeng Qi , Huiping Xing , Yuhu Li . The Use of Viscosity Method for Predicting the Life Expectancy of Xuan Paper-based Heritage Objects. University Chemistry, 2024, 39(8): 290-294. doi: 10.3866/PKU.DXHX202401037
6. [6]
  Yu'ang Liu , Yuechao Wu , Junyu Huang , Tao Wang , Xiaohong Liu , Tianying Yan . Computation of Absolute Electrode Potential of Standard Hydrogen Electrode Using Ab Initio Method. University Chemistry, 2025, 40(3): 215-222. doi: 10.12461/PKU.DXHX202407112
7. [7]
  Meng Lin , Hanrui Chen , Congcong Xu . Preparation and Study of Photo-Enhanced Electrocatalytic Oxygen Evolution Performance of ZIF-67/Copper(I) Oxide Composite: A Recommended Comprehensive Physical Chemistry Experiment. University Chemistry, 2024, 39(4): 163-168. doi: 10.3866/PKU.DXHX202308117
8. [8]
  Lisen Sun , Yongmei Hao , Zhen Huang , Yongmei Liu . Experimental Teaching Design for Viscosity Measurement Serves the Optimization of Operating Conditions for Kitchen Waste Treatment Equipment. University Chemistry, 2024, 39(2): 52-56. doi: 10.3866/PKU.DXHX202307063
9. [9]
  Heng Chen , Longhui Nie , Kai Xu , Yiqiong Yang , Caihong Fang . 两步焙烧法制备大比表面积和结晶性增强超薄g-C₃N₄纳米片及其高效光催化产H₂O₂. Acta Physico-Chimica Sinica, 2024, 40(11): 2406019-. doi: 10.3866/PKU.WHXB202406019
10. [10]
  Naiying Fan , Chuanli Qin , Guo Zhang , Bin Wang , Yan Wang , Bing Zheng , Yichun Qu , Zhiyao Sun , Guanghui An . Case Design of Course Ideological and Political Education in Chemical Experiment Safety: the Safe Use of Common Laboratory Instruments and Glassware. University Chemistry, 2024, 39(2): 242-247. doi: 10.3866/PKU.DXHX202309061
11. [11]
  Hailian Tang , Siyuan Chen , Qiaoyun Liu , Guoyi Bai , Botao Qiao , Fei Liu . Stabilized Rh/hydroxyapatite Catalyst for Furfuryl Alcohol Hydrogenation: Application of Oxidative Strong Metal-Support Interactions in Reducing Conditions. Acta Physico-Chimica Sinica, 2025, 41(4): 100036-. doi: 10.3866/PKU.WHXB202408004
12. [12]
  Wenliang Wang , Weina Wang , Sufan Wang , Tian Sheng , Tao Zhou , Nan Wei . “Schrödinger Equation – Approximate Models – Core Concepts – Simple Applications”: Constructing a Logical Framework and Knowledge Graph of Atom and Molecule Structures. University Chemistry, 2024, 39(8): 338-343. doi: 10.3866/PKU.DXHX202312084
13. [13]
  Tongqi Ye , Qi Wang , Yuewen Ye , Yanqing Wang , Hongyang Zhou , Xianghua Kong . Reflection on the Reform of Physical Chemistry Teaching under the Background of “Intelligent Chemical Engineering”. University Chemistry, 2024, 39(3): 167-173. doi: 10.3866/PKU.DXHX202308116
14. [14]
  Hongmei Zhao , Ziqiang Lu , Song Li , Xingyu Li , Chengting Zi , Xingli Fan , Xiangdong Qin . Exploration and Practice of Physical Chemistry Teaching under the Guidance of Course Ideological and Political Education. University Chemistry, 2024, 39(3): 210-217. doi: 10.3866/PKU.DXHX202309006
15. [15]
  Youjun Fan , Dandan Cai , Wei Chen , Jianhua Qiu . Exploration and Practice of Ideological and Political Education Reform in Physical Chemistry Experiment. University Chemistry, 2024, 39(4): 119-124. doi: 10.3866/PKU.DXHX202310123
16. [16]
  Bing Sun . Practice of Ideological and Political Education in Physical Chemistry Courses for Non-Chemistry Majors. University Chemistry, 2024, 39(8): 28-35. doi: 10.3866/PKU.DXHX202311080
17. [17]
  Jianmin Hao , Ruifeng Wu , Ying Wang , Yijia Bai , Xuechuan Gao , Yuying Du . Reform and Practice of Physical Chemistry Course Based on Enhanced Process Assessment and Evaluation. University Chemistry, 2024, 39(8): 78-83. doi: 10.3866/PKU.DXHX202311103
18. [18]
  Xu Liu , Chengfang Liu , Jie Huang , Xiangchun Li , Wenyong Lai . Research on the Application of Diversified Teaching Models in the Teaching of Physical Chemistry. University Chemistry, 2024, 39(8): 112-118. doi: 10.3866/PKU.DXHX202402021
19. [19]
  Ruming Yuan , Laiying Zhang , Xiaoming Xu , Pingping Wu , Gang Fu . Application of Mathematica in Visualizing Physical Chemistry Formulas. University Chemistry, 2024, 39(8): 375-382. doi: 10.3866/PKU.DXHX202401030
20. [20]
  Congyi Wu . Advice for Young Teachers to Promote Teaching Level of Physical Chemistry. University Chemistry, 2024, 39(11): 15-19. doi: 10.3866/PKU.DXHX202402054

Get Citation

PDF

XML

Metrics

PDF Downloads(0)
Abstract views(1006)
HTML views(122)

通讯作者: 陈斌, bchen63@163.com

1.
沈阳化工大学材料科学与工程学院沈阳 110142

Address：Zhongguancun North First Street 2,100190 Beijing, PR China Tel: +86-010-82449177-888

DownLoad: Full-Size Img PowerPoint

Return