Single Displacement and Redox

1
Single Displacement and Redox
2
Single Displacement and RedoxAt 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
Simple Reactions
Decomposition
Synthesis (Combination)
Single Replacement
Double Replacement
4
Synthesis
A
B
A
B

Decomposition
A
B

A
B
Single Replacement


A
B
A
B
C
C
Double Replacement


A
B
A
B
C
C
D
D
5
Synthesis
A
B
A
B

Decomposition
A
B

A
B
Single Replacement


A
B
A
B
C
C
Double Replacement


A
B
A
B
C
C
D
D
6
3. Single Replacement Reactions

• 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 (-).
• 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!)

7
3. Single Replacement Reactions

• For these reactions, you must remember
• When H2O 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

8
Relative Activities

• Metals Decreasing Activity Halogens
• Lithium, Li Fluorine, F
• Potassium, K Chlorine, Cl
• Calcium, Ca Bromine, Br
• Sodium, Na Iodine, I
• Magnesium, Mg
• Aluminum, Al
• Zinc, Zn Hydrogen, H
• Chromium, Cr Copper, Cu
• Iron, Fe Mercury, Hg
• Nickel, Ni Silver, Ag
• Tin, Sn Platinum, Pt
• Lead, Pb Gold, Au

9
Single Replacement Reactions

• (note Li is higher relative activity than H)

10
A displacement reaction metallic copper with
silver nitrate                                
                                                
            
Cu Ag NO3
Note Cu is higher relative activity
Ag Cu(NO3)2
11
Single Replacement Reactions

• Write and balance the following single
  replacement reaction equation
• Zinc metal reacts with aqueous hydrochloric acid
• Zn(s) HCl(aq) ?
• ZnCl2 H2(g)
• Note Zinc replaces the hydrogen ion in the
  reaction because of higher relative activity

2
12
Single Replacement Reactions

• Now show how the oxidation numbers change for a
  single displacement reaction
• Zn(s) 2 HCl(aq) ? ZnCl2 H2(g)
• Each Zn loses 2e- oxidation, reducing agent
• Each H gains 1e- reduction, oxidizing agent

13
Single Replacement Redox

• Aluminum metal reacts with aqueous copper (II)
  nitrate
• Al(s) Cu(NO3)2(aq)?
• Al(NO3)3(aq) Cu
• 2 Al(s) 3 Cu(NO3)2(aq)? 2 Al(NO3)3(aq)
  3 Cu
• Each Al loses 3e- oxidation, reducing agent
• Each Cu(II) gains 2e- reduction, oxidizing agent

14
Single Displacement and RedoxLets 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

15
Try This

• Predict the products, balance the following
  reactions and show the change in oxidation
  numbers
• Zinc reacts with aqueous copper (II) sulfate
• Zinc is higher relative activity so
• Zn CuSO4 ? Cu ZnSO4
• Each Zn loses 2e- oxidation, reducing agent
• Each Cu(II) gains 2e- reduction, oxidizing agent