Chemistry Forum

Please help.
How to present the influence of HCl on an aqueous solution of H₂S?

How is H₂S dissociated in water? Equation please. What happend with the equlibrium if H+ is added?

aqueous solution of H₂S:
H₂S + H₂O → H₂SO₄


2HCl + H₂SO₄ → Cl₂ + SO₂ + 2H₂O

Are such equations correct?

No

Here it is asked what happend if you dissolve H₂S in water. There is no Oxidation to sulfuric acid.
Write the dissolving and dissociation equation
This is expressed as an equilibrium.
What happens if you add H+ to this equilibrium

dissociation equation H₂S + H₂O -> H₃O(+) + HS(-)

Yes correct. So what happens if HCl will be added.

HCl + HS(-) + H₃O(+) -> Cl(-) + H₂S(-) + H₃O(+)

It is H₂S not H₂S(-). It means the H₂S will be expelled. It get more stunk.

is this the correct form of the equation ?

HCl + HS(-) + H₃O(+) -> Cl(-) + H₃O(+) + H₂S↑

Are the following description and drawing correct?


Reaction on wet indicator paper
H₂S + H₂O = HS + H₃O

Observations:
There is gas coming out of the test tube with a characteristic smell.
Universal test strip turns red when wet.

Conclusions:
The gas that evolves is hydrogen sulfide

This could be misinterpretation, because also HCl fume turn the paper red. Better is to use lead acetate paper which turns Black by PbS.


The chemical reaction could be simplyfied.

H₃O+ + HS- => H₂S + H₂O Adding HCl
Vise versa reaction on pH paper.

Thank you very much!

Reaction on lead acetate paper that turns black by PbS.

It's OK?
H₂S + (CH₃COO)₂Pb → 2CH₃COO + PbS↓

What about the H from H₂S

H₂S + (CH₃COO)₂Pb → 2CH₄COO + PbS↓