Single replacement reaction: Definition, rules, and examples

📚 Quick Study Guide

• ⚛️ A single replacement reaction (also called displacement reaction) is a type of chemical reaction where one element replaces another in a compound.
• 🧪 The general form is: $A + BC \rightarrow AC + B$, where A is a more reactive element than B.
• 🔥 Reactivity is determined by the activity series. A metal can only replace another metal below it in the series. Similarly, a halogen can only replace another halogen below it.
• 📝 Rules to remember:
  • 💡 A more reactive metal will replace a less reactive metal in a compound.
  • 🌊 A more reactive halogen will replace a less reactive halogen in a compound.
  • 🚫 If the element trying to do the replacing is *less* reactive, no reaction will occur (NR).
• 🔑 Example: $Zn(s) + CuSO_4(aq) \rightarrow ZnSO_4(aq) + Cu(s)$. Zinc replaces copper because it's higher in the activity series.

🧪 Practice Quiz

1. Which of the following is the general form of a single replacement reaction?
   1. $AB + CD \rightarrow AD + CB$
   2. $A + B \rightarrow AB$
   3. $A + BC \rightarrow AC + B$
   4. $AB \rightarrow A + B$
2. In the reaction $Mg(s) + 2HCl(aq) \rightarrow MgCl_2(aq) + H_2(g)$, what is being replaced?
   1. Magnesium
   2. Chlorine
   3. Hydrogen
   4. Magnesium Chloride
3. According to the activity series, which metal can replace copper ($Cu$) in a compound?
   1. Silver ($Ag$)
   2. Gold ($Au$)
   3. Platinum ($Pt$)
   4. Zinc ($Zn$)
4. What happens if you try to react $NaCl$ with $Br_2$?
   1. $NaBr$ will form.
   2. $Cl_2$ will form.
   3. No reaction will occur.
   4. $BrCl$ will form.
5. Which of the following is NOT a single replacement reaction?
   1. $Cu(s) + 2AgNO_3(aq) \rightarrow 2Ag(s) + Cu(NO_3)_2(aq)$
   2. $2Na(s) + 2H_2O(l) \rightarrow 2NaOH(aq) + H_2(g)$
   3. $C(s) + O_2(g) \rightarrow CO_2(g)$
   4. $Cl_2(g) + 2KBr(aq) \rightarrow 2KCl(aq) + Br_2(l)$
6. In the reaction $F_2 + 2NaCl \rightarrow 2NaF + Cl_2$, which element is more reactive?
   1. Sodium
   2. Chlorine
   3. Fluorine
   4. Hydrogen
7. What does '(aq)' signify in a chemical equation?
   1. Solid
   2. Liquid
   3. Gas
   4. Aqueous (dissolved in water)