缩液溶液中的快速结构动力学:从质子跳跃到散装粘度
Laura Kacenauskaite1,2, Max Moncada Cohen1, Stephen J Van Wyck1
1Department of Chemistry, Stanford University, Stanford, California 94305, United States.
Journal of the American Chemical Society
|April 29, 2024
概括
缩的HCl溶液具有独特的结构动力学,将质子跳跃和散体粘度与最慢的放松时间 (t3) 联系起来. 这种最慢的动态成分随着度的增加而增加,与纯水不同.
科学领域:
- 物理化学
- 解决方案动力学
- 光谱学
背景情况:
- 在缩的HCl中对质子跳跃和离子光谱进行了充分的研究.
- 缩HCl溶液的结构动力学仍然不太清楚.
- 将HCl与NaCl溶液进行比较有助于阐明离子的作用.
研究的目的:
- 研究度依赖的HCl溶液的结构动态.
- 使用光学异质检测-光学克尔效应 (OHD-OKE) 将HCl动力学与NaCl溶液进行比较.
- 将观察到的动态与质子跳跃和散装粘度联系起来.
主要方法:
- 光学异质检测-光学克尔效应 (OHD-OKE) 的测量.
- 从0.8米到15.5米的度依赖动态的分析.
- 与初始MD模拟和2DIR化学交换实验的文献数据进行比较.
主要成果:
- HCl 和 NaCl 溶液呈现三指数的 OHD-OKE 信号衰变,与纯水中的比特指数衰变不同.
- 最慢的衰变常数 (t3) 与总粘度线性相关.
- 质子跳跃时间与最慢的结构动态放松时间 (t3) 保持一致.
结论:
- //水集群的结构动力学决定了质子跳跃和体积粘度.
- 最慢的放松时间 (t3) 随着HCl度的增加而增加,在纯水中不存在.
- 在HCl中最快的衰变常数 (t1,t2) 类似于纯水的常数,并且随着度的增加而略微增加.
相关概念视频
Mixtures of Acids
680
The pH of a solution containing an acid can be determined using its acid dissociation constant and initial concentration. If a solution contains two different acids, then its pH can be determined using one of several methods depending on the relative strength of the acids and their dissociation constants.
In a strong and weak acid mixture, the strong acid dissociates completely and becomes a source of almost all the hydronium ions present in the solution. In contrast, the weak acid shows...
In a strong and weak acid mixture, the strong acid dissociates completely and becomes a source of almost all the hydronium ions present in the solution. In contrast, the weak acid shows...
680
Titration of a Weak Base with a Strong Acid
4.9K
The titration curve of a weak base like ammonia with a strong acid like hydrochloric acid is the mirror image of the titration curve of a weak acid with a strong base.
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
4.9K
Titration of a Strong Acid with a Strong Base
5.4K
During the titration of a strong acid with a strong base, pH calculations are primarily based on the concentration of residual hydronium or hydroxide ions. Initially, a strong acid like hydrochloric acid fully dissociates, creating hydronium and chloride ions, resulting in a low pH. The addition of a strong base like sodium hydroxide alters the concentration of hydronium ions by neutralizing them. As more base is added, the pH gradually increases. At the equivalence point, all hydronium ions...
5.4K
Polyprotic Acids
29.1K
Acids are classified by the number of protons per molecule that they can give up in a reaction. Acids such as HCl, HNO3, and HCN that contain one ionizable hydrogen atom in each molecule are called monoprotic acids. Their reactions with water are:
29.1K
Composition of Polyprotic Acid Solutions as a Function of pH
519
Polyprotic acids of the type H2M constitute two ionizable protons. As a result, on titration with a base, they exhibit two equivalence points in the titration curve. During titration, the species H2M, HM−, and M2− will be present in the solution at different points. The fractions of H2M, HM−, and M2− present at the various instances of the titration are denoted by α0, α1, and α2, respectively.
A graph with the alpha values is plotted against the volume of...
A graph with the alpha values is plotted against the volume of...
519
Strong Acid and Base Solutions
31.7K
A strong acid is a compound that dissociates completely in an aqueous solution and produces a concentration of hydronium ions equal to the initial concentration of acid. For example, 0.20 M hydrobromic acid will dissociate completely in water and produces 0.20 M of hydronium ions and 0.20 M of bromide ions.
31.7K


