Can lead oxide be reduced by hydrogen

Reduction processes


Copper from iron?


A mixture of 2 g of black copper oxide and 1 g of iron powder is heated in a refractory test tube. After the reaction has ended, the test tube is immediately closed with a stopper and allowed to cool. Crush the cooled residue and examine it carefully under a magnifying glass.


Reddish lumps can be seen in a blue-black mass.

What could have come about?


4 CuO + 3 Fe ---> 4 Cu + Fe


Copper oxide + iron ---> copper + iron oxide


Coal as a reducing agent


A mixture of 5 g copper oxide and 0.5 g fine charcoal powder in

Fill a refractory test tube, clamp it at an angle in a stand and close it with a stopper that carries a curved gas discharge tube, the end of which ends in a test tube with clear lime water. Heat the test tube vigorously on the stand.


The lime water becomes cloudy and a gas escapes. The residue in the test tube contains red lumps. (After cooling, shake several times with water one after the other and carefully pour it off again and again, whereby the excess light coal particles are washed away!)


2 CuO + C ---> 2 Cu + CO


Copper oxide + carbon ---> copper + carbon dioxide

Copper oxide is reduced to copper, while the carbon is oxidized to carbon dioxide (proof of v. CO

2 by lime water)

Redox processes with lead oxide under the soldering tube

Implementation 1:

Make a dimple in a piece of charcoal with a pocket knife, insert 1-2 spatula tips of yellow lead oxide (poisonous!) And glow it for a long time with the tip of a reducing solder pipe flame.



Put the cooled residue on a piece of paper and determine its properties. What forms in the coal pit? metallic, silvery, shiny material, with relatively soft and malleable balls.


Which metal was created? Lead!

Who acted as a reducing agent for the lead oxide? Charcoal


2 PbO + C ---> 2 Pb + CO


Lead oxide + carbon

---> lead + carbon dioxide

If there is a corresponding bubble in the oxidizing flame, there is also a red border of



Reaction of hot iron and water vapor


Put wet quartz sand on the bottom of a refractory test tube, then use a spatula to put a layer of dry iron

Spread out the powder, attach the Rg. almost horizontally to the stand and close it with a stopper through which a gas discharge pipe leads into a pneumatic tub with water. Now slowly heat the iron powder until it begins to glow red and in between brush the sand with the flame so that the water evaporates. When the first gas bubbles have escaped, put a test tube completely filled with water over the mouth of the gas discharge pipe. When the test tube has filled with the evolved gas (can it be water vapor?), First remove the gas discharge tube from the water before the heating is stopped. Check the gas in the test tube for its flammability.


How has the cold iron powder changed in the meantime? It has taken on a brownish color. The oxyhydrogen sample is positive.


What has come about?

Fe + H

2O ---> FeO + H2

Iron + water ---> iron oxide + hydrogen

What follows from the experiment with regard to the composition of the water?

Water is made up of oxygen and hydrogen.

What is the process?

It is a redox reaction in which iron is oxidized and water is reduced.

What other metals, like iron, also develop hydrogen from water vapor when heated?Try zinc ...

Which metals do not react at all with water?

The precious metals in particular gold, platinum ...

Action of calcium on water

Half fill a beaker with water, throw in a few spatula tips of grated calcium and immediately invert a funnel! Place on the bottom of the beaker. How do calcium and water react? - Put a test tube over the funnel tube and (after it has filled with the developed gas) hold the mouth against the flame. Perception? Which gas is produced? - After the reaction has ended (and removal of the funnel), determine the appearance of the liquid and the reaction to phenolptalein solution.

Complete and explain the equations:

a) Ca + H2O ---> .... + ....

b) CaO + H2O ---> Ca (OH)2


Total process: Ca + 2H2O ---> Ca (OH)

2 + ....

The red-violet color of the phenolphthalein solution indicates that in addition to the reduction of water and the oxidation of calcium, a lye must have been formed (calcium hydroxide).