Which of the following is the strongest reducing agent?
Ca2+(aq)
Li+(aq)
Ca(s)
Na(s)
K(s)
ans: K(s)
but I don't understand why it is. I think that li+ is strongest reducing agent b/c E of Li=-3.04 while E of K is -2.92. can someone help me?
Yes, Li is -3.04 but the question is for Li^+ and not Li.
is E of Li+ equals -3.04 as well?
The strength of a reducing agent is determined by the tendency of the species to lose electrons and be oxidized. In general, the lower the reduction potential (E°) value, the stronger the reducing agent.
While it is true that the standard reduction potential for Li+ (-3.04 V) is more negative than that of K+ (-2.92 V), it's important to note that the question specifically asks about the reducing ability of the elements calcium (Ca), lithium (Li), sodium (Na), and potassium (K) in their elemental forms (Ca(s), Li(s), Na(s), and K(s)) and as ions (Ca2+(aq), Li+(aq), Na+(aq), and K+(aq)).
When comparing these elements in their elemental forms, potassium (K) is considered the strongest reducing agent because it has the lowest ionization energy and the highest tendency to lose its outermost electron. This means that potassium has a greater willingness to lose electrons compared to the other elements on the list.
In terms of their reduction potentials as ions, Li+ is indeed a stronger reducing agent compared to K+, but the question is asking about the strength of the reducing agent in its elemental form. Therefore, among the given options, K(s) is the strongest reducing agent.
To determine which of the given species is the strongest reducing agent, we need to compare their reduction potentials. The reduction potential, denoted as E°, is a measure of the tendency of a species to gain electrons and undergo reduction.
You are correct in considering the reduction potentials. The more negative the reduction potential, the stronger the reducing agent. However, you need to make sure you are comparing the reduction potentials of the same species.
In this case, the reduction potentials you mentioned are for the elements Li and K in their standard states (Li+(aq) + e- → Li(s) and K+(aq) + e- → K(s)). These reduction potentials are for the formation of the pure metal from its ions in solution.
To compare the reduction potentials of Ca2+(aq), Li+(aq), Ca(s), Na(s), and K(s), we need to refer to a standard reduction potentials table. The reduction potentials of the ions in solution (Ca2+(aq) and Li+(aq)) can be compared directly, while the reduction potentials of the metals (Ca(s), Na(s), and K(s)) need to be converted to their corresponding ion forms.
By referring to a reduction potentials table, we can find the following values for the reduction potentials:
- Ca2+(aq) | Ca(s): -2.87 V
- Li+(aq) | Li(s): -3.05 V
- Na+(aq) | Na(s): -2.71 V
- K+(aq) | K(s): -2.92 V
According to these values, Li+(aq) has the most negative reduction potential, making it the strongest reducing agent among the given options.
Therefore, it seems that there may be an error in your answer key, as the Li+(aq) species has a more negative reduction potential than K(s), making it the better reducing agent.
In conclusion, among the options provided, Li+(aq) is the strongest reducing agent, not K(s).