Solid iron sulfide combines with aqueous hydrogen chloride to form hydrogen sulfide gas and aqueous iron chloride.

which type of chemical reaction is this an example of?

double-displacement

decomposition

synthesis

single-displacement

Fe2S3 + 6HCl → 3H2S + 2FeCl3 is a double-displacement  reaction

Explanation:

Step 1: The balanced equation

Fe2S3 + 6HCl → 3H2S + 2FeCl3

Step 2:

Decomposition: This is a reaction in which a compound breaks down into two or more simpler substances. Most decomposition reactions require an input of energy in the form of heat, light, or electricity.

The general form of a decomposition reaction is:    AB→A+B

In our case, this is not a decomposition reaction.

Synthesis: This is a type of chemical reaction in which two or more simple substances combine to form a more complex product. The reactants may be elements or compounds, while the product is always a compound.

The general form of a decomposition reaction is:  A + B → AB

In our case, this is not a synthesis reaction.

Single-displacement reaction: This is a reaction in which one element replaces a similar element in a compound. The general form of a single-replacement (also called single-displacement) reaction is:

A+BC→AC+B

In our case, this is not a single-displacement reaction.

Double - displacement reaction: This is a reaction in which the positive and negative ions of two ionic compounds exchange places to form two new compounds. The general form of a double-replacement (also called double-displacement) reaction is:

AB+CD→AD+B

In this reaction,  A  and  C  are positively-charged cations, while  B  and  D  are negatively-charged anions. Double-replacement reactions generally occur between substances in aqueous solution. In order for a reaction to occur, one of the products is usually a solid precipitate, a gas, or a molecular compound such as water.

In our case: There occurs a duble replacement between Fe^3+ and S^2- with H+ and Cl-.

Fe2S3 + 6HCl → 3H2S + 2FeCl3 is a double-displacement  reaction