Humber Admissions Practice Test

What outcome characterizes the products of a double-displacement reaction?

1. They are exclusively gaseous.

2. They may involve a solid and/or liquid.

3. They must produce energy.

4. They usually release heat only.

The correct answer is: They may involve a solid and/or liquid.

The products of a double-displacement reaction may involve a solid and/or liquid, making this answer accurate. In double-displacement reactions, two compounds exchange components, often resulting in the formation of a precipitate (a solid) when one of the products is insoluble in the reaction environment. Alternatively, some reactions can produce a liquid product, such as water, especially when an acid reacts with a base. This type of reaction does not exclusively produce gaseous products, since many double-displacement reactions, particularly those occurring in solution, result in the formation of solids or liquids rather than gases. Additionally, the production of energy is not a defining characteristic of these reactions; while energy changes can occur, such changes are not a requisite aspect of the process. Heat release can happen, but it is not a consistent outcome for every double-displacement reaction, and reactions may also absorb energy rather than release it. Thus, the variety of products—including solids and liquids—captures the essence of what characterizes double-displacement reactions.