The reaction Br2 (l) + 2 K (s) → 2 KBr (s) is classified as a precipitation reaction. In this reaction, bromine (Br2) in its liquid form reacts with potassium (K), a solid metal, to form solid potassium bromide (KBr).
To understand why this is a precipitation reaction, we need to look at the characteristics of precipitation reactions. A precipitation reaction occurs when two soluble reactants combine to form an insoluble product, which precipitates out of the solution. Although in this instance, we are dealing with potassium in its elemental form rather than a soluble reactant, the end result is the formation of a solid compound (KBr) from the reactants.
Furthermore, a neutralization reaction typically involves an acid and a base reacting to form water and a salt. Since there are no acids or bases involved in this reaction, it does not fit the criteria for a neutralization reaction.
In summary, the reaction Br2 (l) + 2 K (s) → 2 KBr (s) is clearly a precipitation reaction because it results in the formation of a solid (KBr) from the reactants.