Lead tree

Demonstration of the laws of electrolysis, described by M. Faraday, can be done with the help of a very interesting experience "growing" a lead tree or as it is called a Saturn tree. Such a name for the obtained plumbum crystals came to us from the time of the alchemists - they called the saturn of Saturn. But first things first...

Demonstration of the laws of electrolysis, described by M. Faraday, can be done with the help of a very interesting experience growing a lead tree or as it is called a Saturn tree

To get a lead tree we need:

  1. glass cuvette or glass;
  2. a cover for it with lead electrodes;
  3. solution of acid plumbum;
  4. a battery of batteries with a voltage of 4,5 - 9 V;
  5. connecting wires with a switch or a switch.

A solution of salt of the acid plumbum is prepared on distilled water, since then it will be the most transparent. However, for this, after dissolution, it is necessary to allow the solution to settle for a while. If the solution is slightly translucent, then it can give a couple drops of essential essence.

Assemble the installation, as in the figure, connect the positive pole of the battery to the central electrode, and the negative - to the side bent. When the chain is closed on the cathode, the plumbum crystals begin to grow in the form of small twigs of leaden wood. The growth rate will be determined by the concentration of the solution (selected experimentally, depending on the experimental conditions), battery voltage, size and relative location of the electrodes.

The best way to see a lead tree is to "grow" it in a flat cuvette, which you can do yourself. To do this, you need two glass plates, between which the bent rubber tube is laid, secure with brackets, for example, of plastic or steel. This cuvette design allows you to design the resulting lead wood to the screen even in a large audience.

Another option to grow a lead tree can be done by doing the following experiment.

In a 500 ml flask, 200 ml of distilled water are poured into it, 2 g of agar-agar, 0,65 g of lead acetate Pb(CH3COO)2 are poured into it and 10-20 drops of glacial acetic acid CH3COOH. The contents of the flask are heated to boiling and boiled until the agar-agar is completely dissolved. Warm solution is poured into a 200 ml beaker and after the solution turns into a jelly in a glass, one large zinc granule is pressed into it at a depth of 1-2 cm. The next day you can see that this granule has "sprouted" and a leaden tree appeared in the glass, which is growing more and more in all directions.

The phenomenon is explained as follows. Metal zinc displaces from lead acetate free metal, which is released in the form of large branched formations:

Zn + Pb(CH3COO)2 = Zn(CH3COO)2 + Pb
.

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