Transcript Collapsing Can

Formation of a Mirror
A solution is added to a flask. Within seconds a
brilliant mirrored surface forms on the inner wall of
the 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
Ag+
reduction
Ag
 The silver metal reduction product
adhered to the glass
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
H
C
O
oxidation
O H
C O
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