Please explain the reaction between Potassium carbonate and Magnesium

Click For Summary

Discussion Overview

The discussion revolves around the chemical reaction between potassium carbonate (K2CO3) and magnesium (Mg), specifically exploring the mechanisms and thermodynamics behind the reaction that produces potassium (K), carbon (C), and magnesium oxide (MgO). Participants seek clarification on the displacement of potassium by magnesium and the role of thermodynamics in this reaction.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions how magnesium can displace potassium in the reaction, seeking an explanation of the underlying chemistry.
  • Another participant suggests that the reaction is similar to reducing oxides, as seen in thermite reactions, emphasizing the importance of thermodynamics over the reactivity series.
  • It is proposed that the reaction is likely driven by the formation of stable magnesium oxide (MgO), which has a high enthalpy of formation.
  • Participants discuss the stability of MgO and its role in driving the reaction, with one participant affirming that the high stability of MgO is a key factor.
  • There is a suggestion that the stability of MgO compared to K2CO3 influences the reaction's tendency to produce MgO.

Areas of Agreement / Disagreement

Participants express varying degrees of understanding and interpretation regarding the reaction mechanism, with some agreeing on the role of MgO stability while others seek further clarification. No consensus is reached on the specifics of the displacement process.

Contextual Notes

Participants reference thermodynamic principles and the reactivity series but do not resolve the complexities of the reaction mechanism or the conditions under which it occurs.

lioric
Messages
335
Reaction score
26
TL;DR
Why does Mg reduce K2CO3 even though K is higher in the reactivity series
I saw this video on YouTube, ()
which shows a person making potassium with the following reaction

K2CO3 + Mg = K + C + MgO

I just don’t understand how Mg can displace K

I googled the reaction but couldn’t find much info on this reaction. Could someone give the name to this, or explain the chemistry behind it? There is a part where he uses KMnO4 and glycerin to start the reaction.

Thank you for your time.
 
Chemistry news on Phys.org
Haven't watched the whole video, but by the sound of it it is in a way similar to reducing oxides like it is commonly done in thermites.

Reactivity series is just part of the picture, and even not the most important one. What really matters when predicting reaction products is thermodynamics: ΔG = ΔH - TΔS (and sometimes kinetics, but that's not the case here). In this particular case reaction is probably driven by the MgO creation, such oxides are very stable and have very high enthalpy of formation (more or less making them produces a lot of heat).
 
  • Like
Likes   Reactions: lioric
Borek said:
Haven't watched the whole video, but by the sound of it it is in a way similar to reducing oxides like it is commonly done in thermites.

Reactivity series is just part of the picture, and even not the most important one. What really matters when predicting reaction products is thermodynamics: ΔG = ΔH - TΔS (and sometimes kinetics, but that's not the case here). In this particular case reaction is probably driven by the MgO creation, such oxides are very stable and have very high enthalpy of formation (more or less making them produces a lot of heat).
Like always sir, you give a great explanation. Cannot count how many times you’ve helped out. Thank you so much. This was great.
 
  • Like
Likes   Reactions: davenn, WWGD and BillTre
Borek said:
Haven't watched the whole video, but by the sound of it it is in a way similar to reducing oxides like it is commonly done in thermites.

Reactivity series is just part of the picture, and even not the most important one. What really matters when predicting reaction products is thermodynamics: ΔG = ΔH - TΔS (and sometimes kinetics, but that's not the case here). In this particular case reaction is probably driven by the MgO creation, such oxides are very stable and have very high enthalpy of formation (more or less making them produces a lot of heat).
Hello Borek👋, so what you're saying is that the whole reaction is possible is because Mg which is an Alkali earth metal has an affinity to form oxides is that it?
 
Redriq1 said:
Hello Borek👋, so what you're saying is that the whole reaction is possible is because Mg which is an Alkali earth metal has an affinity to form oxides is that it?

More like "high stability of MgO is what drives the reaction".
 
  • Like
Likes   Reactions: Redriq1
Borek said:
More like "high stability of MgO is what drives the reaction".
Oooohh so since MgO is more stable than K2CO3 it tends to from MgO in this reaction.. Am i right?
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
5K
Replies
2
Views
5K
  • · Replies 19 ·
Replies
19
Views
9K
  • · Replies 3 ·
Replies
3
Views
3K