Which one of the following is expected to be the strongest Lewis acid?

Fe, Fe+, Fe2+, Fe3+

Which do you think would accept electrons the easier? Fe(s) or Fe^+? Do that same kind of logic on the others one by one.

Fe3+ is expected to be the strongest Lewis acid, as it has the highest charge and is therefore the most likely to accept electrons.

To determine which one of the given species is expected to be the strongest Lewis acid, we need to consider their electron accepting tendencies.

In the Lewis acid-base theory, a Lewis acid is a species that can accept an electron pair, while a Lewis base is a species that can donate an electron pair. The strength of a Lewis acid is related to its ability to accept electrons effectively.

Let's analyze each species one by one:

1. Fe(s) (Iron in its solid state):
Iron in its solid state does not readily accept electrons. Metals, in general, are more likely to act as Lewis bases, i.e., electron donors, rather than Lewis acids. Therefore, Fe(s) is not expected to be a strong Lewis acid.

2. Fe^+ (Iron in its +1 oxidation state):
The Fe^+ ion has lost one electron compared to its neutral state. This electron deficiency makes it more favorable for Fe^+ to accept an electron pair, resulting in a stronger Lewis acid character than Fe(s).

3. Fe^2+ (Iron in its +2 oxidation state):
The Fe^2+ ion has lost two electrons compared to its neutral state. The greater electron deficiency in comparison to Fe^+ makes Fe^2+ an even stronger Lewis acid than Fe^+.

4. Fe^3+ (Iron in its +3 oxidation state):
The Fe^3+ ion has lost three electrons compared to its neutral state. With the highest electron deficiency among the options provided, Fe^3+ is expected to be the strongest Lewis acid.

In summary, based on the electron accepting tendencies, Fe^3+ is expected to be the strongest Lewis acid among the given options.

To determine which one of the following species is expected to be the strongest Lewis acid, we need to consider the electron-accepting ability of each species. Lewis acids are electron acceptors, meaning they have a high affinity for accepting an electron pair.

First, let's consider Fe(s) and Fe+. In its elemental state (Fe(s)), iron (Fe) has a neutral charge and does not have an electron deficiency. Fe+ has a positive charge, indicating that it has one fewer electron compared to the neutral iron atom. Therefore, Fe+ is likely to have a higher electron-accepting ability than Fe(s) because the positive charge creates an electron deficiency.

Moving on to Fe2+, Fe2+ also has a positive charge, indicating that it has two fewer electrons compared to the neutral iron atom. Again, this electron deficiency increases the electron-accepting ability, making Fe2+ a stronger Lewis acid compared to Fe+.

Finally, Fe3+ has a positive charge, indicating that it has three fewer electrons compared to the neutral iron atom. With three positive charges, Fe3+ has the highest electron deficiency among the given options, making it the strongest Lewis acid.

To summarize, in terms of Lewis acid strength:
Fe(s) < Fe+ < Fe2+ < Fe3+
Fe3+ is expected to be the strongest Lewis acid among the options provided.