Single Displacement and Redox

Single Displacement and Redox: At the conclusion of our time together, you should be able to: 1.Identify a basic single displacement reaction 2.Use the reactivity series table to determine if the reaction will take place 3.Show the change in oxidation numbers for a single displacement reaction

3. Single Replacement Reactions Single Replacement Reactions occur when one element replaces another in a compound. Single Replacement Reactions occur when one element replaces another in a compound. A metal can replace a metal (+) OR a nonmetal can replace a halogen (-). A metal can replace a metal (+) OR a nonmetal can replace a halogen (-). element + compound  element + compound element + compound  element + compound A + BC  AC + B (if A is a metal) OR A + BC  BA + C (if A is a halogen) (remember the cation always goes first!)

3. Single Replacement Reactions For these reactions, you must remember: For these reactions, you must remember: When H 2 O splits into ions, it splits into H + and OH - (not H+ and O -2 !!) A single replacement reaction will only occur if the replacement ion has a higher activity than the original ion in the compound To determine this, refer to a relative activity table

Relative Activities Metals Decreasing ActivityHalogens Lithium, LiFluorine, F Potassium, KChlorine, Cl Calcium, CaBromine, Br Sodium, NaIodine, I Magnesium, Mg Aluminum, Al Zinc, ZnHydrogen, H Chromium, CrCopper, Cu Iron, FeMercury, Hg Nickel, NiSilver, Ag Tin, SnPlatinum, Pt Lead, PbGold, Au

Single Replacement Reactions (note: Li is higher relative activity than H): (note: Li is higher relative activity than H):

A displacement reaction: metallic copper with silver nitrate Cu + Ag NO 3 Ag + Cu(NO 3 ) 2 Note: Cu is higher relative activity

Single Replacement Reactions Write and balance the following single replacement reaction equation: Write and balance the following single replacement reaction equation: Zinc metal reacts with aqueous hydrochloric acid Zinc metal reacts with aqueous hydrochloric acid Zn (s) + HCl (aq)  Zn (s) + HCl (aq)  ZnCl 2 + H 2(g) Note: Zinc replaces the hydrogen ion in the reaction because of higher relative activity 2

Single Replacement Reactions Now s how how the oxidation numbers change for a single displacement reaction : Now s how how the oxidation numbers change for a single displacement reaction : Zn (s) + 2 HCl (aq)  ZnCl 2 + H 2(g) Zn (s) + 2 HCl (aq)  ZnCl 2 + H 2(g) Each Zn loses 2e - oxidation, reducing agent Each H gains 1e - reduction, oxidizing agent

Single Replacement Redox Aluminum metal reacts with aqueous copper (II) nitrate Aluminum metal reacts with aqueous copper (II) nitrate Al (s) + Cu(NO 3 ) 2(aq)  Al (s) + Cu(NO 3 ) 2(aq)  Al(NO 3 ) 3(aq) + Cu 2 Al (s) + 3 Cu(NO 3 ) 2(aq)  2 Al(NO 3 ) 3(aq) + 3 Cu Each Al loses 3e - oxidation, reducing agent Each Cu(II) gains 2e - reduction, oxidizing agent

Single Displacement and Redox: Let’s see if you can: 1.Identify a basic single displacement reaction 2.Use the reactivity series table to determine if the reaction will take place 3.Show the change in oxidation numbers for a single displacement reaction

Try This… Predict the products, balance the following reactions and show the change in oxidation numbers : Predict the products, balance the following reactions and show the change in oxidation numbers : Zinc reacts with aqueous copper (II) sulfate Zinc reacts with aqueous copper (II) sulfate Zinc is higher relative activity so… Zinc is higher relative activity so… Zn + CuSO 4  Cu + Z n SO 4 Each Zn loses 2e - oxidation, reducing agent Each Cu(II) gains 2e - reduction, oxidizing agent