The wrong statement among the following is

The conjugate base of \(H_3BO_3\) is \(H_2BO_3^–\).

The correct answer is option 2. The conjugate base of \(H_3BO_3\) is \(H_2BO_3^–\).

Let us delve into each statement in detail:

1. Conjugate acid–base pair differs by a proton:

This statement is correct. According to the Bronsted-Lowry theory of acids and bases:

An acid is a substance that can donate a proton (\(H^+\)).

A base is a substance that can accept a proton (\(H^+\)).

A conjugate acid-base pair consists of two species that are related by the gain or loss of a proton.

For example: \(HA\) (acid) + \(H_2O\) \( \rightleftharpoons \) \(A^-\) (base) + \(H_3O^+\) (conjugate acid)

Here, \(HA\) donates a proton to \(H_2O\), forming \(A^-\) and \(H_3O^+\). \(A^-\) is the conjugate base of \(HA\), and \(H_3O^+\) is the conjugate acid of \(H_2O\).

2. The conjugate base of \(H_3BO_3\) is \(H_2BO_3^–\):

This statement is incorrect. \(H_3BO_3\) is boric acid, which has the formula \(B(OH)_3\). The correct dissociation of boric acid in water is:

\(B(OH)_3 + H_2O \rightleftharpoons B(OH)_2^- + H_3O^+ \)

\(H_2BO_3^-\) would imply that only one proton has been lost, but boric acid can donate up to three protons sequentially, forming \(B(OH)_2^-\) (borate ion) and then \(B(OH)^{2-}\) (metaborate ion) as it loses protons stepwise.

3. Lewis Acid is a species that accepts an electron pair and will have vacant orbitals:

This statement is correct. A Lewis acid is a chemical species that can accept a pair of electrons from another species. This ability to accept an electron pair is what distinguishes it as a Lewis acid. For a molecule or ion to act as a Lewis acid, it must have vacant orbitals. Vacant orbitals are molecular orbitals that are unoccupied by electrons and are available to accept an electron pair from a Lewis base. In the context of Lewis acid-base theory, a Lewis acid interacts with a Lewis base. A Lewis base is a species that donates a pair of electrons to form a coordinate covalent bond with the Lewis acid. The Lewis acid accepts the electron pair into its vacant orbital, forming a bond between the Lewis acid and the Lewis base.

Examples:

Metal Cations: Many metal cations act as Lewis acids because they have vacant d orbitals. For example, in aqueous solutions, transition metal ions like \(Fe^{3+}\), \(Cu^{2+}\), and \(Zn^{2+}\) can act as Lewis acids by accepting electron pairs from water molecules.

Boron Trifluoride \((BF_3)\): \(BF_3\) is a classic example of a Lewis acid. It has an empty p orbital on the boron atom, which can accept a pair of electrons from a Lewis base.

Aluminum Chloride \((AlCl_3)\): \(AlCl_3\) is another Lewis acid. It has an incomplete octet around the aluminum atom, making it electron deficient and capable of accepting electron pairs from Lewis bases.

In summary, the statement correctly identifies the key characteristics of a Lewis acid: its ability to accept an electron pair and the presence of vacant orbitals that facilitate this interaction with Lewis bases. This concept is fundamental in understanding how Lewis acids participate in chemical reactions involving electron pair donation.

4. According to Bronsted–Lowry theory, neutralization is transfer of proton:

This statement is correct. In Bronsted-Lowry theory:

Neutralization is indeed the transfer of a proton (\(H^+\)) from an acid to a base.

For example, in the reaction between hydrochloric acid (\(HCl\)) and ammonia (\(NH_3\)): \(HCl + NH_3 \rightarrow NH_4^+ + Cl^- \).

\(HCl\) donates a proton to \(NH_3\), forming \(NH_4^+\) (ammonium ion, conjugate acid of \(NH_3\)) and \(Cl^-\) (chloride ion, conjugate base of \(HCl\)).

Conclusion: The incorrect statement among the options provided is: (2) The conjugate base of \(H_3BO_3\) is \(H_2BO_3^–\).

The correct conjugate base of \(H_3BO_3\) (boric acid) is \(B(OH)_2^-\), and it can further deprotonate to form \(B(OH)^{2-}\) as per its acidic properties.