水性电解质的非线性导电性:超出第一个维恩效应
Hélène Berthoumieux1, Vincent Démery1,2, Anthony C Maggs1
1UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France.
The Journal of chemical physics
|November 12, 2024
概括
高电场通常会增加电解质导电性 (维也纳效应). 然而,在中度缩的水溶液中,水分子被电场对齐会抑制这种导电率的增加,从而改变离子的行为.
科学领域:
- 物理化学 物理化学
- 电化学 电化学 电化学
- 计算化学的计算化学
背景情况:
- 第一个维恩效应描述了在高电场下强电解质导电性的非线性增加.
- 了解电解质在电场中的行为对于各种电化学应用至关重要.
研究的目的:
- 为了研究电场对中度缩的水性电解质的影响.
- 阐明水分子对齐在改变电解质导电性的作用.
主要方法:
- 用分子动力学模拟来建模电解质的行为.
- 用水分子作为二极体的模型来复制模拟结果.
- 随机密度场理论纳入了异性离子相互作用.
主要成果:
- 第一个维恩效应在中度缩的水性电解质中被抑制,这是由于电场诱导的水分子对齐.
- 这种对齐导致水的电容性下降和异构.
- 计算的离子相关性和纳恩斯特-爱因斯坦导电性校正与模拟结果一致.
结论:
- 水分子对齐显著改变了电解质对高电场的反应.
- 这些发现提供了对电场中的离子-水相互作用的更深入的理解.
- 这项研究提供了一个理论框架,用于预测在这种情况下的电解质行为.
相关概念视频
Theory of Metallic Conduction
1.3K
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
1.3K
Electrolyte and Nonelectrolyte Solutions
62.3K
Substances that undergo either a physical or a chemical change in solution to yield ions that can conduct electricity are called electrolytes. If a substance yields ions in solution, that is, if the compound undergoes 100% dissociation, then the substance is a strong electrolyte. Complete dissociation is indicated by a single forward arrow. For example, water-soluble ionic compounds like sodium chloride dissociate into sodium cations and chloride anions in aqueous solution.
62.3K
Electrolytes: van't Hoff Factor
32.9K
Colligative Properties of Electrolytes
The colligative properties of a solution depend only on the number, not on the identity, of solute species dissolved. The concentration terms in the equations for various colligative properties (freezing point depression, boiling point elevation, osmotic pressure) pertain to all solute species present in the solution. Nonelectrolytes dissolve physically without dissociation or any other accompanying process. Each molecule that dissolves yields one...
The colligative properties of a solution depend only on the number, not on the identity, of solute species dissolved. The concentration terms in the equations for various colligative properties (freezing point depression, boiling point elevation, osmotic pressure) pertain to all solute species present in the solution. Nonelectrolytes dissolve physically without dissociation or any other accompanying process. Each molecule that dissolves yields one...
32.9K
Electrical Conductivity
1.1K
In perfect conductors, the electric field inside is always zero due to the abundance of free electrons, which nullify any field by flowing. As a result, any residual charge resides on the surface.
In a practical conductor, an applied electric field may be sustained, causing a flow of electrons, which produce a current. The differential form of the current, the current density, is related to the electric field.
More generally, it is related to the force per unit charge, which involves the...
In a practical conductor, an applied electric field may be sustained, causing a flow of electrons, which produce a current. The differential form of the current, the current density, is related to the electric field.
More generally, it is related to the force per unit charge, which involves the...
1.1K
Ionic Strength: Effects on Chemical Equilibria
1.4K
The addition of an inert ionic compound increases the solubility of a sparingly soluble salt. For example, adding potassium nitrate to a saturated solution of calcium sulfate significantly enhances the solubility of calcium sulfate. Le Châtelier's principle cannot predict this shift in the equilibrium. Instead, this could be explained in terms of changes in the effective concentration of the ions in solution in the presence of added inert salt.
In this solution, the primary...
In this solution, the primary...
1.4K
Common Ion Effect
41.1K
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Châtelier’s principle. Consider the dissolution of silver iodide:
41.1K


