Question

How is the reaction between hydrogen sulfide and iron chloride possible?

Answer 1

The compound hydrogen sulfide and iron chloride both are soluble in water. The aqueous solution of both compounds reacts with each other to form an insoluble compound along with an acid.

Complete step by step answer:
Hydrogen sulfide is a chemical compound containing two hydrogen atoms and one sulfur atom. The chemical formula of hydrogen sulfide is ${H_2}S$. Hydrogen sulfide is a colorless sulfide gas with rotten egg-like smell.
Iron chloride is a chemical compound containing one iron atom and two chlorine atoms. The chemical formula of iron chloride is $FeC{l_2}$. Iron chloride is also known as ferrous chloride. The oxidation state of iron in iron chloride is 2.
The compound hydrogen sulfide in its aqueous form reacts with aqueous iron chloride to form a solid compound which is insoluble.
The reaction between the hydrogen sulfide and iron chloride is shown below.
${H_2}S + FeC{l_2} \to FeS(s) + 2HCl$
In this reaction, one mole of hydrogen sulfide reacts with one mole of iron chloride to form one mole of iron sulfide and two mole of hydrochloric acid.
Here, the dissociated iron cation reacts with the sulfur anion to form iron sulfide.
It is a type of precipitation reaction. In precipitation reaction, two aqueous solutions of the compound react to form an insoluble compound which is known as precipitate. The formation of precipitate is observed when white solid is formed which settles down in the solution.

Note: In this question reaction of hydrogen sulfide with iron chloride or ferrous chloride is asked and also hydrogen sulfide reacts with iron (III) chloride or ferric chloride.
The reaction is shown below.
$2FeC{l_3} + {H_2}S \to 2FeC{l_2} + 2HCl + S$
Here, two mole of ferric chloride reacts with one mole of hydrogen sulfide to form two mole of ferrous chloride, two mole of hydrochloric acid and one mole sulfur.