Sciencemadness Discussion Board

A yellow substance created when reacting two metal salts in Listerine with citric acid

ejmc64 - 20-11-2018 at 01:39

I did a experiment to see if two salts manganese(III) oxide(s) and sodium bicarbonate(aq) would cause a displacement reaction, the end result was no visible change.

but then I added Listerine (ingredients: water, alcohol 26.9%, benzoic acid, poloxamer 407, sodium benzoate, caramel, Eucalyptol 0.092%, Menthol 0.042%, Methyl salicylate 0.060%, Thymol 0.064%) and citric acid to see if a reaction would occur, I saw fizzing when the citric acid was added, and the solution turned yellow (normally when you add citric acid to a sodium bicarbonate solution it fizzes and generates no color).

so I wonder what products will be formed by this reaction?

[Edited on 20-11-2018 by ejmc64]

j_sum1 - 20-11-2018 at 02:10

I did not tbink Mn (Iii) oxide was soluble. I might be wrong. But it does not surprise me that you saw no displaceme t reaction.

As for the listerine... This is your chance to be systematic. Test with one salt only. Determine the concentration where you first observe your product. Since you know some of the things on the ingredient list, obtain some of these and test in isolation.

Bear in mind that there will be plenty of ingredients not listed: dyes in particular. You might not be able to get to the bottom of this one.

You have not actually given enough details for anyone to help you. We lack details of your product and the reaction conditions.

I recommend so.ething a lot simpler for your experiments. A mixture with this many components is not simple.

MrHomeScientist - 20-11-2018 at 06:12

Quote: Originally posted by ejmc64  
I did a experiment to see if two salts manganese(III) oxide(s) and sodium bicarbonate(aq) would cause a displacement reaction, the end result was no visible change.

Great experiment! You had a hypothesis, used two simple substances, and performed a test with a clear result. Top marks.
Quote:
but then I added Listerine

What? Why? What did you think would happen? If you had a hypothesis to test then that's great, but randomly mixing chemicals together is never a good idea. Things can get dangerous very quickly. A complicated mixture like Listerine is also going to make it near impossible to figure out what happened. Which component caused what reaction? As j_sum said, you don't even know all the possible compounds since they may not all be listed on the bottle.
Quote:
and citric acid to see if a reaction would occur, I saw fizzing when the citric acid was added, and the solution turned yellow (normally when you add citric acid to a sodium bicarbonate solution it fizzes and generates no color).

Correct! Citric acid and sodium bicarbonate is the combination of chemicals used in just about every commercial product that fizzes when put in water. Alka Seltzer, bath bombs, etc. It produces carbon dioxide, sodium citrate, and water as products, so you see a colorless fizzy solution. It's also endothermic, so you may notice it gets colder. But again I have to ask, why? What was your hypothesis in adding citric acid to your two salts that didn't appear to react?
Quote:
so I wonder what products will be formed by this reaction?

Really it's impossible to say with such a complex mixture. If you make a witch's brew, expect magical nonsense.

fusso - 20-11-2018 at 08:24

Quote: Originally posted by MrHomeScientist  

Correct! Citric acid and sodium bicarbonate is the combination of chemicals used in just about every commercial product that fizzes when put in water. Alka Seltzer, bath bombs, etc. It produces carbon dioxide, sodium citrate, and water as products, so you see a colorless fizzy solution. It's also endothermic, so you may notice it gets colder. But again I have to ask, why? What was your hypothesis in adding citric acid to your two salts that didn't appear to react?
Why is this rxn endo?

MrHomeScientist - 20-11-2018 at 09:20

I'm not sure why exactly, just that it is; the reaction needs energy to proceed. Try it out and measure the temperature! I'm sure you can calculate the energy released/absorbed by the reaction, too.

Swinfi2 - 20-11-2018 at 09:35

Imo one obvious reason that contributes to it being endothermic is that gas is given off. More degrees of freedom that the energy of the system has to be shared over. But to really answer this question you should also look into the bond strengths before and after too.. dG = dH - t.dS (G gibbs free energy, H enthalpy, t temp, S entropy)

I suppose this is flawed lagic though because im thinking of the temperature of the solution which is an open system not the exothermic/endothermic definitions which specify closed system. I tink you could have a edge case where it's exothermic but also gets colder

[Edited on 20-11-2018 by Swinfi2]