Predicting the Product in Single Replacement Reactions Using the Activity Series

Introduction 2 NaBr(aq) + Cl2(g) → 2 NaCl(aq) + Br2(l) There are two types of single replacement reactions, A) The metal ion in a solution is replaced by another metal. 2 AgNO3(aq) + Mg(s) → Mg(NO3)2(aq) + 2 Ag(s) B) The halide in a solution is replaced by another halide. 2 NaBr(aq) + Cl2(g) → 2 NaCl(aq) + Br2(l)

Introduction These reactions do not happen all the time! Some metals will replace other metal ions in solution. However, not every metal will replace every other metal ion in a solution. The same is true for the halides. The list of activity or reactivity for these elements is called the “Activity Series.”

Metals Halides The Activity Series: F2 Cl2 Br2 I2 Li Mg Co Sb Ag Rb Al most active most active Li Mg Co Sb Ag Rb Al Ni Bi Pt K Mn Sn Cu Au Ba Zn Pb Hg Sr Cr Ca Fe Na Cd increasing activity increasing activity increasing activity increasing activity increasing activity increasing activity least active least active

Using the Activity Series The activity series is used to predict whether or not a single replacement reaction will occur. First, we look at the ions in a solution, and determine what is being replaced. If the added metal is higher up on the activity series list, then it is more reactive and causes a replacement to occur. If the added metal is lower down on the activity series list, then it is less reactive, and there is no reaction.

Using the Activity Series For example: We put zinc metal in a solution of copper(II) sulfate. Li Mg Co Sb Ag Rb Al Ni Bi Pt K Mn Sn Cu Au Ba Zn Pb Hg Sr Cr Ca Fe Na Cd Zn is more active than Cu. Zn(s) will replace Cu2+(aq). Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)

Using the Activity Series For example: We put magnesium metal in a solution of iron(III) chloride. Li Mg Co Sb Ag Rb Al Ni Bi Pt K Mn Sn Cu Au Ba Zn Pb Hg Sr Cr Ca Fe Na Cd Mg is more active than Fe. Mg(s) will replace Fe3+(aq). 3 Mg(s) + 2 FeCl3(aq) → 3 MgCl2(aq) + 2 Fe(s)

Using the Activity Series For example: We put copper metal in a solution of iron(III) chloride. Li Mg Co Sb Ag Rb Al Ni Bi Pt K Mn Sn Cu Au Ba Zn Pb Hg Sr Cr Ca Fe Na Cd Fe is more active than Cu. Cu(s) will not replace Fe3+(aq). Cu(s) + FeCl3(aq) → no reaction

Using the Activity Series For example: We add chlorine gas to a solution of iron(III) iodide. F2 Cl2 Br2 I2 Cl2 is more active than I2. Cl2 will replace I−. 3 Cl2(g) + 2 FeI3(aq) → 2 FeCl3(aq) + 3 I2(s)

Practice Problems Use the activity series to predict the products of the following reactions. Indicate if there is no reaction. Mg(s) + Cu(NO3)2(aq) → Fe(s) + AgNO3(aq) → Fe(s) + Na2SO4(aq) → Pb(s) + Co(NO3)2(aq) → Mg(NO3)2(aq) + Cu(s) 3 Fe(NO3)3(aq) + 3 Ag(s) no reaction no reaction