Single Replacement Reactions Flashcards

Single Replacement Reactions

Overview

• Single replacement reactions involve one element replacing another in a compound.
• General forms:
  • $A + BC \rightarrow AC + B$
  • $A + BX \rightarrow AX + B$
  • $BX + Y \rightarrow BY + X$

Types

• Metal Cation Replacement: A metal replaces another metal or hydrogen in water/acid.
• Halogen Anion Replacement: A more active halogen replaces a less active halogen.

Metal Reactivity Series

• Predicts whether a single-replacement reaction will occur.
• Metals are ranked by decreasing reactivity; metals higher on the list can replace those lower down.
• Alkali and alkaline earth metals (CBS: Calcium, Barium, Strontium) can replace hydrogen in water.
• Metals above hydrogen in the series can replace $H^+$ in acids.
• Example: $Mg(s) + 2Zn(NO<em>3)</em>2(aq) \rightarrow Mg(NO<em>3)</em>2(aq) + Zn(s)$
• Example: $Zn(s) + 2Mg(NO<em>3)</em>2(aq) \rightarrow$ No reaction!

Halogen Activity Series

• Halogens decrease in activity down the group (F > Cl > Br > I).
• A halogen can replace another halogen below it in the series.
• Example: $2NaCl(s) + F<em>2(g) \rightarrow 2NaF(s) + Cl</em>2(g)$
• Example: $MgCl<em>2(s) + Br</em>2(l) \rightarrow$ No Reaction

Variable Charges

• If a metal can form cations with variable charges, it will form the lowest possible charge in a single replacement reaction.