A single replacement reaction (also known as a single displacement reaction) occurs when one element replaces another element in a compound. Among the given reactions, the one that is a single replacement reaction is:
Fe + 3NaBr → FeBr3 + 3Na
In this reaction, iron (Fe) displaces sodium (Na) in sodium bromide (NaBr), resulting in the formation of iron(III) bromide (FeBr3) and releasing sodium.
The other reactions are different types:
- The first reaction (Ca(OH)2 + H2SO4 → CaSO4 + 2H2O) is a neutralization reaction.
- The second reaction (CH4 + 2O2 → CO2 + 2H2O) is a combustion reaction.
- The third reaction (H2O + CO2 → H2CO3) is a combination reaction, forming carbonic acid.
Thus, the answer is: Fe + 3NaBr → FeBr3 + 3Na (single replacement reaction).