Chemical Forums

General Forums => Generic Discussion => Topic started by: GroundwaterGuy on February 11, 2019, 09:10:33 AM

Title: What is the difference between H2S and S2-?
Post by: GroundwaterGuy on February 11, 2019, 09:10:33 AM

Hi everyone,

I am looking for some insight on Hydrogen Sulphide (H2S) and Sulphide (S2-), specifically in groundwater.

What exactly is the difference between the two?  Is hydrogen sulfide simply just a form of sulphide?  I am asking because in the provincial guidelines for groundwater (well water), there is an aesthetic objective of 0.05mg/L for sulphide (as H2S).  However, some labs that do tests on groundwater report the concentrations simply as S2-.  Can we compare this result directly to the 0.05 limit for H2S?

I would appreciate any help.

Thanks!

Title: Re: What is the difference between H2S and S2-?
Post by: Babcock_Hall on February 11, 2019, 01:02:30 PM

If hydrogen sulfide, H₂S, loses two protons, it becomes a di-anion:  S^2-.  If hydrogen sulfide loses only one proton, it becomes a mono-anion: HS^-.  Does this help?