homemade synthesis of cupric hydroxide
Introduction
I am very young and my journey in chemistry is just beginning. Everything I know I have learned exclusively from books or my own research, but even so I have ventured to carry out several experiments in my own way.
In the past, one of my experiments was electrolysis using seawater. Since I used copper wires, the result was cloudy water which, after researching, I determined was Cu(OH)₂. Since it interested me, I kept trying until I obtained a method that allowed me to create it whenever I wanted.
Observation
As I was able to verify, electricity breaks the chemical bonds in water, forming bubbles of its elements, oxygen and hydrogen. But if the electrodes are copper wires and pencil leads are tied to their tips (essentially so that they do not interfere with the reaction, since I had previously contaminated it by using screws or nails. Also, copper by itself does not electrify the water), the electricity releases Copper(2+) ions that combine with hydroxide(-) ions to form the cupric hydroxide that I observe. Although I am fairly certain that the resulting solid (after evaporation) contains sodium chloride (used to increase the electrical conductivity of the water), and possibly copper oxychloride, because in previous versions of the experiment, the copper wire ended up with a kind of stain or salt that was somewhere between white, green, and light blue (in color). Furthermore, it is the logical outcome considering that sodium chloride would not pass up the opportunity to release chlorine.
Problem
The main problem is that forming it is not as simple as combining electricity + water + copper, because the water does not react very well. That is why I used sodium chloride (although sodium bicarbonate would probably be better because it does not produce the problems associated with copper oxychloride). The electrodes are now graphite pencil leads, since nails produced unwanted iron in the final solution. In the end I was able to solve it in order to produce what is, at least in part, cupric hydroxide.
Hypothesis
I already mentioned it before. As far as I know, when hydroxide (-) ions are released at the anode, they combine with the positive copper ions that are released and remain in the water. Afterwards, that newly formed copper salt remains suspended in the water, although it also contains portions of copper oxychloride (formed by the reaction of copper hydroxide with the negative chlorine released by table salt), as well as salt dissolved in the water.
Experiment
Materials I used:
- 9V battery (photo attached)
- 2 copper wires (3 wires twisted together in each one), one measuring 6.6 cm and the other 6.3 cm.
- 2 pencil leads, one measuring 1.2 cm and the other 1.3 cm.
- 25 g of sodium chloride, or table salt (approximately, because I'm not sure how accurate my scale is).
- Water (approximately 100 to 125 mL)
Steps I followed:
1- Pour all of the available salt into the water.
2- Stir until no salt is visible to the naked eye.
3- Insert the copper wires with the pencil leads tied to their tips.
4- Connect the other end of the wire, without the pencil lead, to the battery (the battery terminals).
5- Wait approximately 5 minutes or longer.
6- Heat it in a water bath long enough for all the water to evaporate.
7- Collect the resulting salt and store it.
Personal notes:
- The water is pale light blue with yellowish tones.
- The wires: • One only darkened on the portion that was submerged. • The other darkened at one specific point. • The one that does not appear to be darkened produced a green flame when placed in fire, but only when the flame reached the portion that had been submerged in the water. (The base copper did not do this; I tested it as well.)
(All of this was carried out on 06/14/2026.)
Conclusions
This is one of the experiments I have performed the most. I would say I have carried out at least 6 different attempts, or perhaps even more. I decided to publish this one because it is the only one that is structured and documented with measurements and everything (Lavoisier and the scientific community of this very subreddit would probably kill me if I published something as poorly structured and improvised as all of my previous attempts). In conclusion, I can say that this process is indeed suitable for obtaining this salt, at least until I manage to get better laboratory equipment than 10 borosilicate test tubes (certified by Francisco H. Walz S.C.A.) and household items.
Final words:
I would absolutely love to receive feedback. I am willing to listen to all your criticism and comments. It has already been a year since I decided that I would dedicate my life to chemistry. Although I am still very far from earning a degree in chemistry, I have an indescribable passion inside me. Every video, everything I do, everything I see related to chemistry fills me with motivation. Every time I explain my experiments, I feel a fire inside me. Whenever I have been depressed or sad, I have turned to reading or spending time with chemistry, one of the few things that has never stopped exciting me or bringing me joy. I can spend an hour locked in my room, completely focused on analyzing my samples, simply because I enjoy it. I came to this subreddit with the mission of finding people who believe in me, and if not, then finding people who enjoy chemistry so I can talk outside an environment where no one understands a single word of what I am talking about. Finally, I would like to quote the words of Marie Curie herself, which perfectly represent a part of my life and the way I see science: "Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less."