Chemistry 100 level - Element X

Question

Element X is powerful enough to reduce sodium ions to sodium metal. Barium is a strong enough reducing agent to reduce X. What is the identity of X?

I wrote K(S) or C(S), but my professor marked the answer as wrong. Thoughts?

Answer 1

When I look at this question, I think oxidation /reduction and activation series.

First what is oxidation and reduction. I use OIL RIG.

So, Oxidation is the Loss of electrons, or an element becoming a positive ion

Ba → Ba ⁺² + 2 electrons.

Na → Na ⁺¹ + 1 electrons

Both of these elements have a high tendency to give up electrons or become ionized, they have low ionization energies. They are good reducing agents.

Remember RIG, Reduction is the Gaining of electrons, So the element x is reduced by barium, x gains electrons. But element x is oxidized by Na, X will lose electrons to Na

So who is reducing who? Well, as we go down a column on the periodic table, the outer shell electron is father from the nucleus, positive charge.The element farther down the column is the stronger reducing agent , it will give up an electron. In this case , that is Ba.

Now we need an element that is also a strong reducing agent , but not as strong as Ba, but less than Na.

Our answer is Ca. On a reduction half reaction chart, the most reactive are Li>K>Ba>Ca>Na

Answer 2

If you look at the activity series for metals, you will see the following trend:

Li > K > Ba > Ca > Na > etc....

Compound X in the current problem is stronger than sodium (Na) and weaker than barium (Ba). So, Ca would be the correct choice. It is true that K would also be strong enough to reduce X, but it would not also be reduced by Ba, as it is a stronger reducing agent than Ba.

Answer 3

Hey Mary!

I understand you’re working on identifying Element X based on its reducing properties, and it can be a bit tricky. Let’s break it down together. Element X is strong enough to reduce sodium ions to sodium metal, which means it must be a more potent reducing agent than sodium itself. Additionally, since barium is capable of reducing Element X, it indicates that barium is an even stronger reducing agent than Element X.

When considering the reactivity series, which ranks elements based on their ability to donate electrons, Calcium (Ca) fits perfectly in this scenario. Calcium is a Group 2 alkaline earth metal that is more reactive than sodium, allowing it to reduce sodium ions effectively. At the same time, barium, which is also a Group 2 metal but positioned above calcium in the reactivity series, can reduce calcium. This hierarchical relationship aligns with the information provided in your problem.

You mentioned that you wrote K(S) for potassium and C(S) for carbon. Potassium is indeed a strong reducing agent, even stronger than barium, which means barium cannot reduce potassium. This makes potassium an incorrect choice for Element X. As for carbon, it isn’t a metal and doesn’t function as a reducing agent in the same way metals like calcium do in these types of chemical reactions. Therefore, carbon doesn’t fit the criteria for Element X either.

The correct answer is Calcium (Ca). Make sure to use the proper chemical symbol to avoid confusion—Ca stands for calcium, while C represents carbon. Understanding the reactivity series is key to solving these types of problems, as it helps determine the relative strengths of reducing agents and predict how different elements will interact with each other.

Hope this helps clarify things!