- #1
so-crates
- 293
- 0
Is there any reason for order the activity series of ions in aqueous solutions? For example, why is Calcium higher than sodium?
Why is the activity series of ions in aqueous solutions ordered?
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Discussion Overview
The discussion revolves around the ordering of the activity series of ions in aqueous solutions, specifically questioning why calcium is ranked higher than sodium. Participants explore concepts related to ionization energy, hydration energy, and the underlying reasons for the observed order.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant questions the rationale behind the activity series, specifically asking why calcium is ranked higher than sodium.
- Another participant suggests that the difference in ranking can be explained by comparing ionization energy and hydration energy, indicating that calcium has a higher calculated potential than sodium.
- A later reply challenges the relevance of hydration energy, stating that the ions do not react with hydrogen and questioning its significance in the context of the activity series.
- A correction is made regarding the terminology, clarifying that the correct term is "hydration" energy, not "hydratation," and explaining that hydration energy relates to the interaction of ions with water molecules.
Areas of Agreement / Disagreement
Participants express differing views on the importance of hydration energy in the context of the activity series, indicating that there is no consensus on its relevance. The discussion remains unresolved regarding the fundamental reasons for the ordering of the activity series.
Contextual Notes
There are limitations in the discussion regarding the assumptions made about ion interactions and the definitions of terms used, particularly concerning hydration energy and its implications for the activity series.
- #2
Borek
Mentor
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so-crates said:
Long ago I have a discussion on a similar subject with one of my professors at Uni. It went like this (I was answering):
Q: Why is calcium higher than sodium?
A: When you take ionization energy and hydratation energy for both ions and you calculate potentials, calcium is higher then sodium.
Q: OK, but why is calcium higher than sodium?
A: Because when you take into account the results of the quantum cacluations you get such ionization and hydratation energy, that calculated potential for calcium is higher than potential for sodium.
Q: OK, but why is calcium higher than sodium?
A: Eeee... Because that's a way it is?
Q: OK, good. Let's move to another question.
Later I have learned that "Because that's a way it is" is the answer for most chemistry questions - you may look for reasons, but the final answer is always "Because that's a way it is"
- #3
so-crates
- 293
- 0
What would the hydration energy have anything to do with it? The ions aren't reacting with hydrogen.
- #4
Borek
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so-crates said:
OK. its hydration, not hydratation, but it has nothing to with hydrogen. Every ion in the solution is surrounded by the water particles - the are dipoles so they are electrically attracted. Amount of energy involved when the water particles are forming ordered layers is called hydration energy.
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