Formation of a Mirror

A solution is added to a flask. Within seconds abrilliant mirrored surface forms on the inner wall ofthe flask

Purpose

To observe a silver plating reaction

Demonstration Sugar was one of the solutions in the

flask

A silver ion solution was the other solution

Oxidation of the carbon occurred when silver ion was reduced

The silver metal reduction product adhered to the glass

Ag+ Agreduction

Concepts

1. Redox Reactions

2. Selective Organic Reactions

1. Redox Reactions In a redox reaction, one substance loses

electrons while another substance gains electrons

“Redox” is a conventional term which is a combination of the words “reduction” AND “oxidation”

The substance that loses electrons is said to be oxidized and/or the reducing agent

The substance that gains electrons is said to be reduced and/or the oxidizing agent

2. Selective Organic Reactions Organic compounds may be totally

oxidized to carbon dioxide and water

gasoline oxidation (combustion)

Organic compounds may be selectively oxidized by adding an oxygen atom to just one carbon

C O C O

H HOoxidation

Conclusions The formation of silver metal

was due to the reduction of silver ion

The reducing agent for silver ion was the sugar

The sugar was simultaneously oxidized as the silver ion was reduced

Comments Oxidation (the loss of electrons) of

one specie is always accompanied by the reduction (the gain of electrons) of another specie

The reaction in this demonstration is the “Tollen’s Reaction” and is a test for the presence of oxidizable sugars