OT: Rust Stains on Ceramic Floor Tile

Naval Jelly is HCL. CLR is acid, but other acids. They aren't as strong as HCL (Muratic Acid). What was the stain you were trying to clean? Obviously they claim CLR will remove rust. Did it not clear away a rust stain?

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Rick

HF is very strong acid. We used that to etch glass. No need at all to use HF for cleaning unless you want to get glass *very* clean, wettable clean. But then there are other reagents for that too.

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Rick

on

      ...Jim Thompson         |    mens     |         |     et      |    |           |  |   |

od.

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      ...Jim Thompson     ...Jim Thompson       |    mens     |     |     et      |  |       |

you mean like making homeade gunpowder [charcoal, sulfur, saltpeter] gasoline based flamethrowers [at least 30 foot range, but no gel], and silencers [slightly shot self in middle finger tip while holding structure over barrel]

Robert Macy schrieb:

Hello,

HF is very dangerous:

Bye

My recollection is that Naval Jelly is Phosphoric Acid, not Hydrochloric Acid.

Bot will remove rust; the issue is what else they will remove and thus damage.

Joe Gwinn

That is correct.

The Naval Jelly worked a peach, though one spot required a great amount of "elbow grease" ;-) ...Jim Thompson

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I love to cook with wine.     Sometimes I even put it in the food.

Either my recollection is faulty or they changed the formula over the years. I recall looking at the label some 30+ years ago and noting that it was HCL. But certainly I could be mistaken.

As you say, either will remove rust and both are rather strong acids. Highly concentrated phosporic acid is about pH 1.0. I just looked up the pH of HCl and it's pH is *negative*! I never heard of negative pH before... lol

Then again, your stomach contents are pH 2.0, so what is "strong" exactly?

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Rick

I just looked at the MSDS. It's Phosphoric Acid, plus a dash of Sulfuric, but no HCl.

I don't think pH can be negative: .

Strong acids are also discussed.

Joe Gwinn

It's the front porch, with Bluestone steps and casiron railing. The rust from the railings has stained the bluestone. The CLR didnt do a thing. Murtic acid might work. But that is nasty stuff, even at 10%hcl.

Cheers

exactly?

So, he should puke on the rust stains? ;-)

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Yeah, that's it! Pour Coke all over the bluestone! ;-)

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According to the MSDS, you are correct - 10-30% phosphoric acid, a trace of sulphuric acid, a phosphate ester, isopropanol, and a polysaccharide gelling agent. Presumably the remainder (non-listed ingredients) are water and miscellaneous contaminants.

No HCL listed.

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Either my recollection is faulty or they changed the formula over the years. I recall looking at the label some 30+ years ago and noting that it was HCL. But certainly I could be mistaken.

As you say, either will remove rust and both are rather strong acids. Highly concentrated phosporic acid is about pH 1.0. I just looked up the pH of HCl and it's pH is *negative*! I never heard of negative pH before... lol

Then again, your stomach contents are pH 2.0, so what is "strong" exactly?

--

Rick 

pH is -log[H+], where [H+] is the concentration of free hydrogen ions  
expressed as moles per liter.  Concentrated HCl is about 11.0 moles per  
liter, so if the HCl is completely dissociated in concentrated HCl, which is  
what they teach in freshman chemistry among other gross simplifications,  
then the nominal pH of concentrated HCl is -1.04. 

Bret Cannon

There is nothing stops the pH being negative it is simply the log(hydrogen ion concentration ratio)

HCl has a negative pH for any solution of above about 3% wt/wt

HBr and HI are even stronger acids in water but less common.

The original problem of cleaning the rust marks off might also be done with the less aggressive citric acid available from home brew centres. The acid isn't strong but it does reduce brown iron(III) to soluble green iron(II) and is less likely to damage ceramic surface finishes.

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Regards, 
Martin Brown

Ahh. It's been a long time since I took Chemistry. OK. You might consider editing the Wiki article.

Yes. Ceramics are mostly acid-proof, but surfaces like marble are another matter.

Oxalic acid is the traditional rust remover. Actually, Bar-Keepers Friend is oxalic acid, so that might be an easy way to buy the acid.

Joe Gwinn

The Wiki article is right in that 1 mol/kg HCl is about 36.5g/kg or

3.65% wt wt which is about pH 0. What it fails to say is that HCl is so very soluble in water that you can get upto 38% wt wt and pH -1.1.

It is rather difficult to measure this pH accurately in practice as most kit misreads under extreme pH at either end of the scale.

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Regards, 
Martin Brown

This would be a useful thing to add to the Wiki article, which anybody can edit.

How does one measure this, then? Or is it by analysis only?

Joe Gwinn