Why is the equation for a sodium-sulfur battery reaction considered 'not right'?

[Creaturemagic]

2Na + 3S --> Na2 + S3^2-

Homework Statement

So I have the equation 2Na + 3S --> Na2 + S3^2- (the 2- being the charge of S3)
This is the reaction generated in a sodium-sulfur battery.
And all's good there, I can see there are two electrons transferred in the reaction and I know it's a redox reaction. However when I handed in my draft for this piece of assessment, I got it back with the comment that this reaction didn't look 'right'.

The task at hand is to summarise an article (Mine being on Electric Cars) and then write four 'focus' questions and model answers. So the reaction is taken straight from the article and I just don't see how it isn't right.

Thanks for any help clearing this up, I plan to ask my teacher tomorrow, so I'll keep this updated.

 

[chemisttree]

If you mean 2Na + 3S <----> Na₂S₃,
then you have it right.

http://books.google.com/books?id=VIFnWIBq_wUC&pg=PA7&lpg=PP1&output=html_text

 

[Borek]

Or change Na₂ to 2Na⁺...

 

[epenguin]

It could well not look right because that is not everyday chemistry - you will have seen it works in quite hairy conditions not to be reproduced in a school laboratory.

I don't know anything but looking at this http://en.wikipedia.org/wiki/Sodium–sulfur_battery and the book extract it looks like it's a mix of polysulfides all the way down and even further than S₃^2- so, as they say it's a bit of a convention to fix on S₃^2-. I expect you can get some S₂^2- and S^2-, perhaps they are not wanted.

 

[DeeNos]

Homework Equations

N/A

The first thing to note is that the equation provided is not balanced. This means that the number of atoms of each element on the reactant side does not equal the number of atoms of each element on the product side. In order for a chemical reaction to accurately represent what is happening, it must be balanced.

Secondly, the charges on each side of the reaction are not balanced. In a redox reaction, the number of electrons lost by the reducing agent must equal the number of electrons gained by the oxidizing agent. In the given equation, there are two electrons lost by the reducing agent (2Na) and three electrons gained by the oxidizing agent (S3^2-). This does not follow the basic principles of redox reactions and therefore, the equation is not considered accurate.

Furthermore, the products of the reaction do not match the expected products for a sodium-sulfur battery. In a sodium-sulfur battery, the expected products are Na2S4 and Na2S2, not Na2 and S3^2-. This suggests that the equation provided may be incorrect or incomplete.

In conclusion, the equation for the sodium-sulfur battery reaction provided is not considered accurate because it is not balanced, the charges are not balanced, and the products do not match the expected products for this type of battery. It is important to have accurate equations in scientific research and analysis in order to properly understand and predict the outcomes of reactions.