Copper Chloride Bleach

[Raghu Kuvempunagar]

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]

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]

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]

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]

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]

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]

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]

Increase the concentration of both copper sulfate and chloride?