Answer:
The reaction 2 H₂O + 2 K (s) → 2 KOH (1) + 2H₂ (g) is single-displacement (option A)
Step-by-step explanation:
A single-displacement reaction is a reaction in which an element of a compound is substituted by another element involved in the reaction. The general form of a simple substitution reaction is:
AB + C → A +BC
where C and A are pure elements; C replaces A within compound AB to form a new co, placed CB and elementary A.
A single-displacement reaction is characterized by a place of exchange of cations or anions with another to form a new product. A begins as an ion in the solution and appears elementally in the reaction products. In case of reagent C it starts in its elemental form and ends as an ion in an aqueous state forming compound BC.
On the other hand, in a decomposition reaction, a single substance decomposes, producing two or more different substances. The atoms that form a compound are separated to give the products according to the formula:
AB → A + B
Finally, combustion reactions are reactions where oxygen intervenes as a reagent. Oxygen has the ability to combine with various elements to produce oxides, where then oxidation is the combination of oxygen with another substance.
Taking into account all the previously stated definitions, you can see that the reaction 2 H₂O + 2 K (s) → 2 KOH (1) + 2H₂ (g) is single-displacement (option A)