Copper Chloride Bleach

Raghu Kuvempunagar · Aug 3, 2019

1] Is Copper Chloride bleach, for all practical purposes, the same as Copper Sulphate + Sodium Chloride bleach?

2] What role does an acid such as Sulphuric Acid or Acetic Acid play in Copper Chloride (or Copper Sulphate + Sodium Chloride) bleach?

Rudeofus · Aug 3, 2019

Yes, there are even some bleach formulas out there which use Copper Sulfate and Sodium Chloride, both of which are about the cheapest ingredients you can mix a working bleach from. Copper Sulfate/Chloride is very acidic but very weakly buffered, and the tiniest amount of alkali carry over may raise pH to the point where Copper Hydroxide precipitate forms. Addition of acid effectively prevents that.

Raghu Kuvempunagar · Aug 3, 2019

Thanks Rudy. So acid is there for buffering. I measured pH of my brew of Copper Sulphate + Sodium Chloride bleach, one that doesn't have acid, using pH paper. It's around 4.

Rudeofus · Aug 4, 2019

To be honest, pH 4 seems a bit high. Since Copper forms very insoluble hydroxides and oxides, I would expect pH to be close to buffering point of Sulfuric Acid or Hydrochloric Acid. Someone privately communicated me a pH of 0.8 for Copper Sulfate plus Sodium Chloride bleach.

Poor buffering plus the strong color of Copper Sulfate may well influence your measurement with pH strips.

I am far away from home right now, so I can't chime in with my own measurements for now.

Raghu Kuvempunagar · Aug 4, 2019

According to this webpage pH of 0.2M Copper Sulphate solution is 4.

https://pubchem.ncbi.nlm.nih.gov/compound/Copper-sulfate-pentahydrate#section=pH&fullscreen=true

If this information is correct then adding equal amount of Sodium Chloride shouldn't change the pH significantly. So my measured pH of 4 doesn't seem so weird.

Raghu Kuvempunagar · Aug 4, 2019

Raghu Kuvempunagar said:
According to this webpage pH of 0.2M Copper Sulphate solution is 4.

https://pubchem.ncbi.nlm.nih.gov/compound/Copper-sulfate-pentahydrate#section=pH&fullscreen=true

If this information is correct then adding equal amount of Sodium Chloride shouldn't change the pH significantly. So my measured pH of 4 doesn't seem so weird.

And according to this webpage, pH of 0.2M solution of Copper Chloride is 3.6.

https://pubchem.ncbi.nlm.nih.gov/co...Other-Experimental-Properties&fullscreen=true

Raghu Kuvempunagar · Mar 1, 2020

Raghu Kuvempunagar said:
Thanks Rudy. So acid is there for buffering. I measured pH of my brew of Copper Sulphate + Sodium Chloride bleach, one that doesn't have acid, using pH paper. It's around 4.

With sulphuric acid, the bleach has a pH around 1. The action of the bleach is faster with the acid. Still it's a lot slower than dichromate bleach.

Is there an effective accelerator for copper chloride bleach?

koraks · Mar 1, 2020

Increase the concentration of both copper sulfate and chloride?

Copper Chloride Bleach

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