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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: camurgo on September 09, 2019, 08:02:54 PM

Title: The Reaction between lime sulfur and HCL
Post by: camurgo on September 09, 2019, 08:02:54 PM
Hi, I'm an engineering dropout (planning to go back), my background in chemistry isn't so strong but I'm deeply interested.

I'm trying to understand the reaction between lime sulfur and hydrochloric acid (HCL).
It is said that lime sulfur is composed mainly of calcium polysulfides, of general formula CaSx, where x varies from 2 to 7. (That is, CaS2,CaS3,CaS4,CaS5...) It is also said that the reaction between lime sulfur and HCL produces copious amounts of hydrogen sulfide (H2S). But how exactly does this happen?

Wouldn't it make more sense that hydrogen polysulfides (H2S2, H2S3, H2S4, H2S5..) and calcium chloride (CaCl2) were the products?

The equations I imagine should be:
 CaSx + 2HCL -> H2Sx + CaCl2  (where, in both counts, x varies from 2 to 7)

Could it be that hydrogen polysulfides are in fact being produced but some type of disproportionation reaction is breaking them down into H2S ?

Would anyone know anything about this?
Thank you.
Title: Re: The Reaction between lime sulfur and HCL
Post by: chenbeier on September 10, 2019, 02:25:12 AM
The Polysulfides are not stable in acidic environments.
You will get sulfur.

CaSx + 2HCl => CaCl2 +H2S + (x-1) S