How are the Arrhenius and Bronsted-Lowry acid-base definitions different? How are they similar?

How are the Arrhenius and Bronsted-Lowry acid-base...

Key Concepts

Non-Aqueous Bronsted-Lowry Acids

Acids that act as proton donors in the Bronsted-Lowry sense but do not necessarily release H+ ions in water include substances like gaseous hydrogen chloride (HCl) and acids in non-aqueous solvents such as acetic acid in glacial (anhydrous) form. These acids can donate a proton in reactions even when they are not in an aqueous environment, illustrating the broader applicability of the Bronsted-Lowry framework compared to the Arrhenius definition.

Comparison of Arrhenius and Bronsted-Lowry Theories

Both theories relate to acid-base behavior, but they approach it differently. While Arrhenius focuses on the production of specific ions in water (H+ or OH–), the Bronsted-Lowry definition is based on the transfer of protons and does not require a particular solvent. Despite these differences, both definitions converge on the idea of chemical species causing change in proton concentration in a reaction.

Non-Aqueous Bronsted-Lowry Bases

Examples of bases that qualify as Bronsted-Lowry bases but not Arrhenius bases include ammonia (NH3) and the amide ion (NH2–). Ammonia, for instance, accepts a proton to form the ammonium ion (NH4+) without initially producing hydroxide ions in water, thereby fitting the Bronsted-Lowry definition outside of an aqueous context, while the amide ion also accepts protons directly without necessarily generating OH– in water.

Arrhenius Acid-Base Theory

This concept defines acids as substances that increase the concentration of H+ ions when dissolved in water and bases as substances that increase the concentration of OH– ions in aqueous solution. It is limited to aqueous environments, meaning that a substance must generate ions in water to be classified as an acid or base according to Arrhenius.

Bronsted-Lowry Acid-Base Theory

This theory broadens the definition by identifying acids as proton (H+) donors and bases as proton acceptors, regardless of the solvent. It emphasizes the transfer of a proton between species and is applicable in both aqueous and non-aqueous environments, making it more general than the Arrhenius definition.

Transcript

00:04 In the first part of this question, we are asked to name how arhenous acids and bases are different compared to bronch and lower acids and bases.

00:19 And then we are asked what are the similarities when it comes to their definitions.

00:25 So let's look at the differences first.

00:28 And the main differences in these definitions are obvious when it comes to the definition of the basis.

00:35 So the ionius definition tells us that a base will produce hydroxyl ions in water.

01:04 And the bronson -lory definition tells us that a base is a proton acceptor.

01:18 So the bronson -lory definition is a broader definition that will allow us to classify a wide range of chemicals as bases, while the arrhenius definition is a more narrow definition that want to classify many compounds that act like bases to be bases.

01:43 So other than this main difference, there is also the fact that arhanius acids and bases are only defined in water.

02:01 So the acids and the bases in this case have to be.

02:06 Dissolved in water and that is not the case for bronz and lorry acids and bases they can be defined in any type of solvent and even in air so those are the two main aspects that are different in the two definitions now let's focus on the similarities and the similarity in these two definitions is mainly when it comes to the definition of acids.

03:10 So the arrhenius acid -based definition tells us that an acid will produce hydroxyl, i'm sorry, hydronium ions or h -plus ions.

03:39 So the h -plus ions that are formed will react with water to form the hydronium h -3 -o -plus.

03:48 Ions.

03:49 We'll like that a little better.

03:59 That's a 3 in 0 and a plus.

04:04 So acids will produce h plus ions and then according to the bronson glory definition acids donate protons.

04:31 So it's pretty much the same thing.

04:32 Producing a proton and donating a proton is pretty much saying that it will give away a proton.

04:40 So in that way, the two definitions agree on what is an acid...

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