It is a type of chemical reaction wherein an element and a compound reacts to form a new element and a new compound.
A. single replacement
B. synthesis
C. metathesis
d. double replacement
The correct answer and explanation is :
The correct answer is A. single replacement.
Explanation:
A single replacement reaction, also known as a single displacement reaction, is a type of chemical reaction in which an element reacts with a compound, and in the process, one of the elements in the compound is replaced by the free element. As a result, a new element and a new compound are formed.
The general form of a single replacement reaction is:
$$
A + BC \rightarrow AC + B
$$
Here, element $A$ replaces element $B$ in the compound $BC$, forming a new compound $AC$ and a new free element $B$.
For example, consider the reaction between zinc and hydrochloric acid:
$$
\text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2
$$
In this reaction, zinc (Zn), a free element, reacts with hydrochloric acid (HCl) to form zinc chloride (ZnCl₂), a new compound, and hydrogen gas (H₂), which is the new element released.
Why it’s a single replacement reaction:
- In a single replacement reaction, a single element (like Zn) replaces another element (like H) in a compound.
- This leads to the formation of a new compound (ZnCl₂) and the release of the displaced element (H₂ gas).
Why the other options are incorrect:
- B. Synthesis: This type of reaction involves the combination of two or more simple substances to form a more complex compound. For example, A + B → AB.
- C. Metathesis: This is another name for a double replacement reaction, where the cations and anions of two compounds are exchanged to form new compounds (e.g., AB + CD → AD + CB).
- D. Double replacement: Involves the exchange of ions between two compounds to form two new compounds, typically in aqueous solutions, but no single element replaces another.
Thus, the defining characteristic of the single replacement reaction is that an element replaces another element within a compound to form a new compound and a new element.