Question 29

Combination reactions always form only one product.

In combination reactions, multiple reactants combine to produce a single product. This characteristic is fundamental to the definition of combination reactions.

A) Involve only one reactant.

This option is incorrect because combination reactions specifically involve two or more reactants that combine to form one product. Therefore, stating that they involve only one reactant contradicts the definition of this type of reaction.

B) Involve an element and a compound.

While some combination reactions may involve an element and a compound, this is not universally true for all combination reactions. Combination reactions can also occur between two compounds or two elements, making this option too restrictive.

C) Form only one product.

This option is correct as it aligns with the definition of combination reactions, which are characterized by the merging of reactants to yield a single product. This singular product formation is essential to classifying a reaction as a combination reaction.

D) Require oxygen gas.

This option is incorrect because combination reactions do not inherently require oxygen gas. While some combination reactions may involve oxygen, many do not, and thus it cannot be considered a definitive characteristic of all combination reactions.

Conclusion

The correct answer is that combination reactions always form only one product, which is a defining trait of this type of chemical reaction. The other options fail to accurately represent the nature of combination reactions, either by misrepresenting the number of reactants involved, being too restrictive in the types of reactants, or incorrectly implying the necessity of a specific reactant like oxygen.