Single Replacement Reactions — Trading Partners
25 reacciones
In a single replacement (single displacement) reaction, a free element replaces another element within a compound. The general form is A + BC -> AC + B, where element A displaces element B. Whether a reaction occurs depends on the relative reactivity of the elements — the activity series of metals (or halogens) predicts which replacements are thermodynamically favorable. This concept is central to electrochemistry and corrosion science.
Mecanismo de reacción
The activity series ranks elements by their tendency to lose electrons (be oxidized). A more reactive metal displaces a less reactive one from solution. Zinc (higher in the activity series) displaces copper from copper sulfate solution: Zn + CuSO4 -> ZnSO4 + Cu. The zinc atoms lose electrons and go into solution as Zn2+ ions, while Cu2+ ions gain those electrons and deposit as solid copper. This electron transfer makes single replacement reactions a subset of redox reactions.
Ejemplos cotidianos
Dropping a steel nail into copper sulfate solution turns the nail copper-colored as iron displaces copper. Galvanized steel uses zinc coatings that preferentially corrode instead of the underlying iron — a sacrificial single replacement. The thermite reaction (2Al + Fe2O3 -> Al2O3 + 2Fe) is a dramatic single replacement used in welding railroad tracks, reaching temperatures above 2,500 degrees C.
Importancia industrial
Hydrometallurgy uses single replacement to extract metals from ores. Copper cementation recovers copper from mine drainage by passing it over scrap iron. The Kroll process extracts titanium by reducing titanium tetrachloride with magnesium. Single replacement principles underpin all galvanic cells (batteries) — the difference in reactivity between two metals creates the voltage that powers our devices.
Safety Note
Some single replacement reactions are violent — alkali metals react vigorously with water, and the thermite reaction produces molten iron. Always check the activity series before attempting displacement reactions and use appropriate shielding for exothermic reactions.
Aluminio reaccionando con ácido clorhídrico
2Al + 6HCl → 2AlCl₃ + 3H₂
Aluminum reacts with hydrochloric acid to produce aluminum chloride and hydrogen gas. The reaction requires the initial dissolution of the …
Aluminio reaccionando con óxido de hierro(III) (termita)
2Al + Fe₂O₃ → Al₂O₃ + 2Fe
The thermite reaction involves aluminum reducing iron(III) oxide to produce aluminum oxide and molten iron. This spectacularly exothermic reaction generates …
Aluminio reduciendo óxido de cromo (aluminotermia)
2Al + Cr₂O₃ → Al₂O₃ + 2Cr
Aluminum reduces chromium(III) oxide in an aluminothermic reaction similar to the iron thermite reaction. The reaction produces aluminum oxide and …
Calcio reaccionando con agua
Ca + 2H₂O → Ca(OH)₂ + H₂
Calcium reacts with water to produce calcium hydroxide (limewater) and hydrogen gas. The reaction is moderately vigorous, producing a milky …
Carbono reduciendo óxido de hierro en el alto horno
2Fe₂O₃ + 3C → 4Fe + 3CO₂
Carbon (from coke) reduces iron(III) oxide to produce iron metal and carbon dioxide. This is the simplified overall reaction in …
Cinc desplazando al cobre del sulfato de cobre
Zn + CuSO₄ → ZnSO₄ + Cu
Zinc metal displaces copper from copper sulfate solution because zinc is more reactive than copper in the activity series. The …
Cinc reaccionando con ácido clorhídrico
Zn + 2HCl → ZnCl₂ + H₂
Zinc granules react with hydrochloric acid to produce zinc chloride and hydrogen gas. This is a moderately vigorous reaction commonly …
Cinc reaccionando con ácido sulfúrico
Zn + H₂SO₄ → ZnSO₄ + H₂
Zinc reacts with dilute sulfuric acid to produce zinc sulfate and hydrogen gas. This is a straightforward single replacement reaction …
Cloro desplazando al bromo del bromuro de sodio
Cl₂ + 2NaBr → 2NaCl + Br₂
Chlorine gas displaces bromine from sodium bromide solution because chlorine is a stronger oxidizing agent than bromine. The colorless solution …
Cloro desplazando al yodo del yoduro de potasio
Cl₂ + 2KI → 2KCl + I₂
Chlorine displaces iodine from potassium iodide solution because chlorine is more electronegative and a stronger oxidizer than iodine. The solution …
Cobre desplazando a la plata del nitrato de plata
Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
Copper metal displaces silver from silver nitrate solution because copper is more reactive than silver. Silver crystals grow on the …
Estaño reaccionando con ácido clorhídrico
Sn + 2HCl → SnCl₂ + H₂
Tin reacts slowly with hydrochloric acid to produce tin(II) chloride (stannous chloride) and hydrogen gas. Tin is relatively low in …
Flúor desplazando al cloro del cloruro de sodio
F₂ + 2NaCl → 2NaF + Cl₂
Fluorine, the most reactive element, displaces chlorine from sodium chloride to form sodium fluoride and chlorine gas. Fluorine is so …
Hidrógeno reduciendo óxido de cobre
H₂ + CuO → Cu + H₂O
Hydrogen gas reduces copper(II) oxide to metallic copper and water when heated. The black copper oxide powder turns to reddish-brown …
Hierro desplazando al cobre del sulfato de cobre
Fe + CuSO₄ → FeSO₄ + Cu
Iron metal replaces copper in copper sulfate solution because iron is higher in the reactivity series than copper. An iron …
Hierro reaccionando con ácido clorhídrico
Fe + 2HCl → FeCl₂ + H₂
Iron dissolves in hydrochloric acid to produce iron(II) chloride and hydrogen gas. The reaction proceeds at a moderate rate, producing …
Hierro reaccionando con cloruro de cobre(II)
Fe + CuCl₂ → FeCl₂ + Cu
Iron replaces copper in copper(II) chloride solution because iron is more reactive. The green copper(II) chloride solution turns pale green …
Litio reaccionando con agua
2Li + 2H₂O → 2LiOH + H₂
Lithium reacts steadily with water to produce lithium hydroxide and hydrogen gas. While still vigorous, lithium is the least reactive …
Magnesio reaccionando con ácido clorhídrico
Mg + 2HCl → MgCl₂ + H₂
Magnesium reacts vigorously with hydrochloric acid to produce magnesium chloride and hydrogen gas. The reaction is highly exothermic and proceeds …
Magnesio reaccionando con ácido nítrico
Mg + 2HNO₃ → Mg(NO₃)₂ + H₂
Magnesium reacts with dilute nitric acid to produce magnesium nitrate and hydrogen gas. With concentrated HNO3, nitrogen oxides form instead …
Magnesio reaccionando con ácido sulfúrico
Mg + H₂SO₄ → MgSO₄ + H₂
Magnesium reacts vigorously with dilute sulfuric acid to produce magnesium sulfate (Epsom salt) and hydrogen gas. The reaction is rapid …
Magnesio reaccionando con vapor de agua
Mg + H₂O → MgO + H₂
Magnesium reacts with steam to produce magnesium oxide and hydrogen gas. The reaction is vigorous and highly exothermic. Hot magnesium …
Plomo desplazando a la plata del nitrato de plata
Pb + 2AgNO₃ → Pb(NO₃)₂ + 2Ag
Lead metal displaces silver from silver nitrate solution, demonstrating that lead is more reactive than silver. Silver crystals deposit on …
Potasio reaccionando con agua
2K + 2H₂O → 2KOH + H₂
Potassium reacts even more violently with water than sodium, instantly producing potassium hydroxide and hydrogen gas. The hydrogen ignites immediately …
Sodio reaccionando con agua
2Na + 2H₂O → 2NaOH + H₂
Sodium metal reacts violently with water to produce sodium hydroxide and hydrogen gas. The reaction is so exothermic that the …