Justify the continued use of the Arrhenius definition of acids and bases, despite the development of the more sophisticated Brönsted–Lowry definition. Why does the neutralisation of any strong acid in an aqueous solution by any strong base always result in a heat of reaction of approximately -57 kJ mol⁻¹?

SSCE HSC Chemistry Properties of Acids and Bases: Justify the continued use of the

Justify the continued use of the Arrhenius definition of acids and bases, despite the development of the more sophisticated Brönsted–Lowry definition - HSC - SSCE Chemistry - Question 29 - 2011 - Paper 1

Question 29

Justify the continued use of the Arrhenius definition of acids and bases, despite the development of the more sophisticated Brönsted–Lowry definition. Why does the ... show full transcript

Worked Solution & Example Answer:Justify the continued use of the Arrhenius definition of acids and bases, despite the development of the more sophisticated Brönsted–Lowry definition - HSC - SSCE Chemistry - Question 29 - 2011 - Paper 1

Step 1

Justify the continued use of the Arrhenius definition of acids and bases, despite the development of the more sophisticated Brönsted–Lowry definition.

96%

114 rated

Answer

The continued use of the Arrhenius definition can be justified for several reasons:

Simplicity and Accessibility: The Arrhenius definition is straightforward and easy to understand, making it a useful starting point for those new to the study of acids and bases. This simplicity aids in teaching foundational concepts in chemistry.
Historical Context: The Arrhenius definition laid the groundwork for the study of acid-base chemistry. Its historical significance means it remains in use for basic applications and educational contexts, providing context for more advanced theories like the Brönsted–Lowry definition.
Applicability in Certain Reactions: Many reactions, especially in a high school chemistry context, can be adequately explained using the Arrhenius definitions. For example, the dissociation of strong acids and bases in aqueous solutions can often be effectively understood through this model, providing students with practical insight.

Thus, while the Brönsted–Lowry definition offers a broader perspective on acid-base behavior, the Arrhenius definition remains valid in specific situations.

Step 2

Why does the neutralisation of any strong acid in an aqueous solution by any strong base always result in a heat of reaction of approximately -57 kJ mol⁻¹?

99%

104 rated

Answer

The neutralisation of strong acids and bases is generally an exothermic reaction, releasing a consistent amount of heat. This heat release, approximately -57 kJ mol⁻¹, arises from the formation of water from hydronium ions (H₃O⁺) from the acid and hydroxide ions (OH⁻) from the base. The reaction can be represented as follows:

$H^+ (aq) + OH^- (aq) \rightarrow H_2O (l)$

This reaction is highly favorable, leading to a consistent heat release across various strong acids and bases due to the strong interaction in the resultant water molecule, along with the dissolution of salts formed during neutralisation.

Justify the continued use of the Arrhenius definition of acids and bases, despite the development of the more sophisticated Brönsted–Lowry definition - HSC - SSCE Chemistry - Question 29 - 2011 - Paper 1

Worked Solution & Example Answer:Justify the continued use of the Arrhenius definition of acids and bases, despite the development of the more sophisticated Brönsted–Lowry definition - HSC - SSCE Chemistry - Question 29 - 2011 - Paper 1

Justify the continued use of the Arrhenius definition of acids and bases, despite the development of the more sophisticated Brönsted–Lowry definition.

Why does the neutralisation of any strong acid in an aqueous solution by any strong base always result in a heat of reaction of approximately -57 kJ mol⁻¹?

Join the SSCE students using SimpleStudy...