Which of these is a single replacement reaction?
A) Ba(NO3)2+NiSO4→BaSO4+Ni(NO3)2
B) 2Fe+3Br2→2FeBr3
C) CaCl2+Na2CO3→CaCO3+2NaCl
D) Fe+CuSO4→Cu+FeSO4
1 Answer
(D)
Explanation:
A single-replacement reaction (also called a single-displacement reaction) is one in which a pure element and a compound react chemically so that the products include another pure element and a different compound via exchanging of two species.
In other words, it is where an element reacts with a compound and replaces one component of the compound:
Let's examine each option:
- (A)
Option (A) is the reaction
Ba(NO3)2+NiSO4→BaSO4+Ni(NO3)2 This is a typical example of a double-replacement reaction (or double-displacement reaction), in which two substances exchange their cations to form two new substances:
Since this is obviously not a single-replacement reaction, we can eliminate (A).
- (B)
Option (B) is the reaction
2Fe+3Br2→2FeBr3 This is what's called a synthesis (or combination) reaction, where two reactants combine to form only one product:
This is not a single-replacement reaction, so we can also eliminate (B).
- (C)
Option (C) is the reaction
CaCl2+Na2CO3→CaCO3+2NaCl This, like answer (A), is a double-replacement reaction, so we eliminate (C).
This leaves us with one final option:
- (D)
Option (D) is the reaction
Fe+CuSO4→Cu+FeSO4 We can see from the color code that this is a single replacement reaction, conforming to the first image above, so option (D) is correct.
