Brine electrolysis with alluminum

In summary: Assuming your electrodes were aluminium foil, the carbon coating could make the percipitate look grey.
  • #1
Mniazi
57
1
I did an electrolysis with alluminum eletrodes, the electrolyte was NaCl, After completing it the left over was a gresyish precipitate (I assume aluminum hydroxide), I put most of it for evaporating in a cup, the rest evaporated leaving a jell, then later crystals. are the crystals NaCl which is covering the left over hydroxide or is it Sodium Alluminate.
 
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  • #2
I'm sorry you are not finding help at the moment. Is there any additional information you can share with us?
 
  • #3
Firstly, sodium can not form a compound with aluminium. They are both metals, and except for rare cases, metals do not form compounds with each other.
Secondly, the percipitate is probably Al(OH)3 like you suspected. Generally, Al(OH)3 is a fine whitish percipitate. However, if your electrodes were aluminium foil, then the carbon coating could make the percipitate look grey,

Next, depending on how long the electrolysis ran, your crystals could be NaCl or NaClO, assuming you used an undivided cell. I highly doubt you ran it long enough for there to be any appreciable amount of NaClO in the solution, and you probably would have said that it smells like bleach. So, I am assuming the crystals are NaCl.

Generally, using NaCl as an electrolyte is not a good idea due to the evolution of chlorine gas, which is VERY dangerous. If you let it go long enough in an undivided cell with NaCl electrolyte, formation of NaClO (and Cl2 gas dissolving in the solution) will turn it yellow.
So, if your solution did not turn yellowish, your crystals are probably NaCl.
 
  • #4
cpman said:
Firstly, sodium can not form a compound with aluminium. They are both metals, and except for rare cases, metals do not form compounds with each other.

Aluminates are quite common, http://en.wikipedia.org/wiki/Sodium_aluminate

In general, binary compounds (like caesium auride) are rare, but many metals are amphoteric and capable of producing salts - Al, Zn, Cr, Mn being the best known examples.
 
  • #5


Based on the information provided, it is likely that the crystals are a mixture of sodium chloride (NaCl) and sodium aluminate (NaAlO2). During the electrolysis process, the aluminum electrodes would have reacted with the sodium chloride electrolyte to produce aluminum hydroxide (Al(OH)3) and hydrogen gas (H2). The aluminum hydroxide would then have further reacted with the remaining sodium chloride to form sodium aluminate. As the solution evaporated, the sodium chloride and sodium aluminate would have crystallized out of the solution, resulting in a mixture of both compounds. It is also possible that some of the aluminum hydroxide may have remained in the solution and formed crystals as well. Further analysis would be needed to determine the exact composition of the crystals.
 

1. What is brine electrolysis with aluminum?

Brine electrolysis with aluminum is a chemical process that uses an electric current to break down a saltwater solution (brine) into its component elements, namely chlorine gas, hydrogen gas, and aluminum metal.

2. How does brine electrolysis with aluminum work?

The process involves passing an electric current through the brine solution, which causes the sodium and chloride ions to separate. The chlorine ions move towards the anode (positive electrode) and are oxidized to form chlorine gas, while the hydrogen ions move towards the cathode (negative electrode) and are reduced to form hydrogen gas. At the same time, the aluminum ions in the solution are reduced at the cathode to form aluminum metal.

3. What is the purpose of brine electrolysis with aluminum?

Brine electrolysis with aluminum is primarily used to produce chlorine gas, which is a key ingredient in the production of bleach, PVC, and other industrial chemicals. The hydrogen gas produced can also be used as a fuel source, while the aluminum metal can be used in various industrial applications.

4. What are the advantages of brine electrolysis with aluminum over other methods?

One of the main advantages of this method is that it is a cost-effective and environmentally friendly way to produce chlorine gas. It also allows for the production of multiple products (chlorine gas, hydrogen gas, and aluminum metal) from a single process.

5. Are there any potential drawbacks to brine electrolysis with aluminum?

One potential drawback is the energy consumption required for the process, as a significant amount of electricity is needed to break down the brine solution. Additionally, the production of chlorine gas can be hazardous if not properly controlled and monitored.

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