Types of Chemical Reactions- Spontaneous Redox Reactions

Spontaneous Redox Reactions

Description: One of many examples is when zinc metal is placed in a solution of copper sulfate, the copper is reduced and appears as black coating on the zinc. Other examples of redox reactions include:

SnCl2(HCl) + 2Ce(SO4)2(HCl) → Sn(IV) + 2Ce(III) + 2Cl–(aq) + 4SO4-2(aq)    yellow to clear 

5SnCl2(HCl) + 2KMnO4(HCl) + 12H+ → 5Sn(IV) + 2Mn(II) + 2K+(aq) + 10Cl–(aq) + 6H2O(l)    purple to clear pink 

10KI(aq) + 2KMnO4(HCl) + 16H+(aq) → 5I2(aq) + 2Mn(II) + 8H2O(l)               purple to brown 

3SnCl2(HCl) + K2Cr2O7(aq) + 14H+(aq) → 3Sn(IV) + 2Cr(III) + 7H2O(l)           orange to blue 

5H2O2(aq) + 2KMnO4(HCl) + 6H+(aq) → 8H2O(l) + 5O2(g) + 2Mn(II)               purple to clear with gas 

NH4OH(aq) + KMnO4(aq) + ∆ → MnO2(s) + NO3-(aq) + K+(aq)      purple to dark green 

2KI(aq) + HCl + H2O2(aq) → I2(aq) + 2H2O(l)                     clear to brown                                            

Cu(s) + 2AgNO3(aq) + 2H+(aq) → Cu(NO3)2(aq) + 2Ag+(aq) + H2O(l)             clear to blue 

Cu(s) + 2HNO3(conc) → Cu(NO2)2(s) + 2NO2(g)                               clear to green to blue with brown gas 

Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)                                                       blue to clear with solid 

 Source: UW Card Catalog

Year: N/A Vol: N/A Page: N/A

Keywords: Zinc, Copper sulfate, Reduction, Spontaneous

Rating:

Hazard: Medium

• Aquatic toxicity hazard
• Acute toxicity hazard – oral
• Corrosive to metals
• Oxidizer
• Serious eye damage

Effectiveness: Good

• Good connection from demo to course material
• Mild effects are seen by audience
• High reliability
• Time to results is medium
• Results are observable with guidance

Difficulty: Low

• Simple procedures
• Simple manipulations for most to perform
• Use of toxic reagents

Safety precautions:

• Gloves required
• Eye protection required
• Absorbent materials on hand
• Avoid exposure to droplets, vapors, or mists
• Prevent release to the environment

Class: Redox Reactions, Thermodynamics, Electrochemistry

Division: General, Analytical Chemistry,  Inorganic Chemistry

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