Write a chemical eqution that shows that hydrogen sulphide dissolving in water and write a sentence to explain why the solution will conduct electricity?

1 Answer

bandmanjoe's profile pic

bandmanjoe | Middle School Teacher | (Level 2) Senior Educator

Posted on

Hydrogen sulfide (H2S) is slightly soluble in water and acts as a weak acid.  As a weak acid, it dissociates initially into the hydrosulfide ion, HS- (pKa=6.9), and then the sulfide ion, S2- (pKa=11.96).  The presence of the hydronium ion, H3O+ is also present.  The presence of all these intermediary ions is sufficient to conduct the flow of electrical current through the solution.

The formulas would be as follows:

H2S  + H2O  --->  HS-   +  H3O+

HS-  +  H2O  --->   S--   +   H3O+

The solution is initially clear, but clouds up over time due to the slow reaction of hydrogen sulfide with the oxygen in the water.  Over time, elemental sulfur is precipitated out of the solution.

Hydrogen sulfide is a gas at room temperature and has a very disagreeable odor, similar to that of sewer gas or rotten eggs.  When combined with elemental oxygen at high temperatures, it can produce elemental sulfur and water, known as the Clauss reaction.