The overall reaction for the generation of an NO₂⁺ electrophile: can be stated in two separate, reversible steps as a protonation followed by a decomposition (Reactions 1 and 2) .
Reaction 1
Reaction 2Which molecule acts as a Lewis acid, but NOT as a Brønsted-Lowry acid, in these reactions?

Question

The overall reaction for the generation of an NO₂⁺ electrophile:

The overall reaction for the generation of an NO<sub>2</sub><sup>+</sup> electrophile: can be stated in two separate, reversible steps as a protonation followed by a decomposition (Reactions 1 and 2) . <strong>Reaction 1</strong> <strong>Reaction 2</strong>Which molecule acts as a Lewis acid, but NOT as a Brønsted-Lowry acid, in these reactions? A) H<sub>2</sub>SO<sub>4</sub> B) HNO<sub>3</sub> C) H<sub>2</sub>NO<sub>3</sub><sup>+</sup> D) NO<sub>2</sub><sup>+</sup>

can be stated in two separate, reversible steps as a protonation followed by a decomposition (Reactions 1 and 2) .

Reaction 1

Reaction 2Which molecule acts as a Lewis acid, but NOT as a Brønsted-Lowry acid, in these reactions?

Quizplus · Accepted Answer

11ecba2d_1220_8aee_a3bf_53ac770e5811_MD0008_00 By the Brønsted-Lowry definitions, an acid is a molecule that donates a proton (H⁺ ion), and a base is a molecule that accepts a proton. Although the Brønsted-Lowry definitions are sufficient to identify acids and bases in most cases, these definitions are inadequate for molecules that lack acidic protons in their structure yet exhibit acid-base behavior. To overcome this limitation, the Lewis definitions were developed. Accordingly, a Lewis acid is defined as an electron pair acceptor, and a Lewis base is defined as an electron pair donor. In Reactions 1 and 2, all chemical species except H₂O and NO₂⁺ follow the Brønsted-Lowry definition of acid-base behavior. Notably, NO₂⁺ lacks H atoms and cannot be classified by the Brønsted-Lowry definition. However, in the reverse reaction of Reaction 2, the NO₂⁺ electrophile accepts a pair of electrons donated by H₂O. Therefore, applying the Lewis definitions of acids and bases, H₂O is acting as a Lewis base (electron pair donor) and NO₂⁺ is acting as a Lewis acid (electron pair acceptor). (Choice A) Although the H⁺ ion acts as a Lewis acid (electron pair acceptor), H₂SO₄ functions as a Brønsted-Lowry acid by donating H⁺ ions. (Choice B) HNO₃ acts as a Brønsted-Lowry base (H⁺ acceptor) and also as a Lewis base (electron pair donor) in Reaction 1, but HNO₃ does not act as a Lewis acid (electron pair acceptor). (Choice C) H₂NO₃⁺ is an H⁺ donor (Brønsted-Lowry acid) in the reverse of Reaction 1 and decomposes in Reaction 2. Educational objective: A Lewis acid is a molecule that acts as an electron pair acceptor, and a Lewis base is a molecule that acts as an electron pair donor. The Lewis definitions more broadly define acids and bases to include some compounds that lack acidic protons.

The Overall Reaction for the Generation of an NO2+ Electrophile

The Overall Reaction for the Generation of an NO₂⁺ Electrophile