Man's physical universe

xanabras

I

gain

598 MAN IS MASTERING HIS MATERIAL WORLD

This reaction is typical of all displacement reactions in that it involves

a transfer of electrons.

Electrolysis, Which Is Cell Action in Reverse, Is Also an Oxidationreduction

Reaction.

When metals are plated by electrolysis, the metal goes into solution

at one electrode and plates out at the other; thus, in silver-plating, a

brass spoon may be used as one electrode and a bar of silver as the

other electrode, the electrolyte being a solution of some silver salt.

Electrons are sent to the brass spoon and are taken up by the silver

ions surrounding the brass spoon to form metallic silver, which is then

deposited as a plate on the spoon.

of electrons J

Ag"*" + electrons >- Ag"

silver ions

metallic silver

This reaction is clearly electronization (reduction). At the other

electrode electrons are removed from the silver to form silver ions.

Ag"

—>- Ag+ 4- electrons

[loss of electrons t

This reaction is de-electronization (oxidation).

Electrolysis Is a Very Important Metallurgical Process.

The following metals are now produced or refined by electrolysis:

sodium, aluminum, magnesium, zinc, lead, copper, nickel, cadmium,

bismuth, cobalt, and berylHum.

Fifty years ago the price of metallic sodium was $2.00 per pound;

today it is $0.14 per pound. The world production of sodium exceeds

300,000 tons per year. Sodium was formerly used to separate aluminum

from its compounds, but it is now used as a reducing agent

chiefly in the organic chemical industry.

In 1886, 16 metric tons of aluminum were produced at a cost of

about $8.00 per pound; in

1941 the Aluminum Company of America

in the United States alone produced 200,000 tons of aluminum at

about $0.17 per pound; this company's production in 1941, as

its $200,000,000 expansion program neared completion, exceeded

300,000 tons; in 1942, 350,000 tons. In 1941 the Reynolds Metal

Company was producing 50,000 tons; and the United States Government

planned to build plants to produce an additional 600,000

tons of aluminum per year to meet the needs of an expanding airplane

industry. The entrance of the United States into World War II

considerably expanded the above production program.

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