[calculus_jy]

there are sources which state ammonia as a catalyst for the solvay (ammonia-soda) process whilst my teacher says that it is not
from my understanding -a catalyst provides alternate pathway for a chemical reaction with lower activation energy -but does that apply only to elementry chemical reactions in which case ammonia will not count as a catalyst ?

[nj_bartel]

I think the reason your prof is saying that is because (I believe) HCl is a byproduct of that reaction, which consumes some of the ammonia (acid-base reaction).

[calculus_jy]

 have i posted the wrong process?? or have you posted in wrong thread? because i dont think there is HCl in solvay process for production of Na₂CO₃ if i am wrong tell me

[macman104]

Catalysts are also species in a reaction that can be recycled over and over.

If you look at the process, ammonia is consumed, but from that, NH4Cl is made.  Then at a later step, NH4Cl is consumed the produces NH3, which is recycled back into the reaction.  So in the end, you have an almost 0 gain/loss of NH3, and thus it can in a sense be called a catalyst.

[Borek]

I understand the logic behind calling ammonia the catalyst, but I would not call it this way.

[calculus_jy]

and the reason? and so is it a catalyst or not? i have a yes;no=1;1 . i am quite confused now...

[Borek]

I would not call a catalyst substance that doesn't lower activation energy - it doesn't here. I would not call a catalyst substance that gets consumed in the process - and ammonia gets consumed.

Ammonia changes reaction pathway changing solution pH and removing produced HCl, and it gets consumed in the process. It is then reclaimed in separate reaction.

At least thats my understanding of the situation.