What is a BrØnsted -Lowry acid?
A Brønsted-Lowry acid, named after the Danish chemist Johannes Nicolaus Brønsted and the English chemist Thomas Martin Lowry, is a concept in acid-base chemistry that defines an acid as a substance that can donate a proton (H+) to another substance. This definition is broader than the more traditional Arrhenius definition of an acid, which defines an acid as a substance that produces H+ ions (protons) when dissolved in water.
In the Brønsted-Lowry acid-base theory:
1. An acid is a substance that can donate a proton (H+ ion).
2. A base is a substance that can accept a proton (H+ ion).
The key idea here is the transfer of protons from one substance to another. When an acid donates a proton, it becomes a conjugate base, and when a base accepts a proton, it becomes a conjugate acid. This theory allows for a broader understanding of acid-base reactions beyond just those that occur in aqueous solutions, making it more versatile in describing various chemical reactions.
For example, in the reaction between hydrochloric acid (HCl) and water (H2O), HCl donates a proton to water:
HCl + H2O → H3O+ (hydronium ion) + Cl-
In this reaction, HCl is the Brønsted-Lowry acid because it donates a proton (H+), and water is the Brønsted-Lowry base because it accepts the proton to form a hydronium ion (H3O+).
布朗斯特-洛瑞酸是酸碱化学领域的一个概念，得名于丹麦化学家约翰内斯·尼古拉斯·布朗斯特和英国化学家托马斯·马丁·洛瑞。它定义了酸是一种能够将质子（H+离子）捐赠给其他物质的物质。这个定义比传统的阿尔伦尼乌斯酸的定义更广泛，后者将酸定义为在水中溶解时会产生H+离子（质子）的物质。
根据布朗斯特-洛瑞酸碱理论：
1. 酸是一种能够捐赠质子（H+离子）的物质。
2. 碱是一种能够接受质子（H+离子）的物质。
The Brønsted-Lowry theory is a fundamental concept in chemistry and is widely used to describe acid-base reactions in various chemical and biological systems.
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Which one of the following is a BrØnsted -Lowry acid?
A. All of the above
B. HNO2
C. HF
D. CH3COOH
E. (CH3)3NH+
To determine which of the given substances is a Brønsted-Lowry acid, we need to identify which ones can donate a proton (H+ ion) to another substance.
In the Brønsted-Lowry theory:
- An acid is a substance that can donate a proton (H+ ion).
Let's evaluate each of the options:
A. "All of the above" is not a specific substance, so it cannot be considered a Brønsted-Lowry acid.
B. HNO2: This is nitrous acid. It can donate a proton (H+) to form NO2- (the nitrite ion). So, HNO2 is a Brønsted-Lowry acid.
C. HF: This is hydrofluoric acid. It can donate a proton (H+) to form F- (the fluoride ion). So, HF is a Brønsted-Lowry acid.
D. CH3COOH: This is acetic acid, commonly known as vinegar. It can donate a proton (H+) to form the acetate ion (CH3COO-). So, CH3COOH is a Brønsted-Lowry acid.
E. (CH3)3NH+: This is trimethylammonium ion. It can donate a proton (H+) to form (CH3)3N (trimethylamine). So, (CH3)3NH+ is a Brønsted-Lowry acid.
So, the correct answer is:
A. All of the above
All of the substances listed (HNO2, HF, CH3COOH, and (CH3)3NH+) are Brønsted-Lowry acids because they can donate a proton (H+ ion) to other substances.