Sulfuric acid 5N

DeletedAcct1 · Aug 30, 2024

I need the sulfuric acid for the permanganate bleach and all I can get is as 5N (normal).
What concentration equals 5N?

fgorga · Aug 30, 2024

I am not sure that I quite understand your question because 5 N IS a concentration!

In order to given you a proper answer, we really need to know what concentration of sulfuric acid the recipe you are using calls for.

However, I'll make an educated guess that your recipe calls for concentrated sulfuric acid which is 18 M or 36 N. You can use the 5 N in place of the concentrated as long as you account for the differences in volume.

For example, if your recipe calls for 100 mL of concentrated you would need to use 36/5 = 7.2 x 100 = 720 mL of the 5 N AND use 720-100 = 620 mL less of water as you make up the final solution.

Hope this helps.

DeletedAcct1 · Aug 30, 2024

fgorga said:
I am not sure that I quite understand your question because 5 N IS a concentration!

In order to given you a proper answer, we really need to know what concentration of sulfuric acid the recipe you are using calls for.

However, I'll make an educated guess that your recipe calls for concentrated sulfuric acid which is 18 M or 36 N. You can use the 5 N in place of the concentrated as long as you account for the differences in volume.

For example, if your recipe calls for 100 mL of concentrated you would need to use 36/5 = 7.2 x 100 = 720 mL of the 5 N AND use 720-100 = 620 mL less of water as you make up the final solution.

Hope this helps.

My bad, I mean what 5N equals % in weight?
The acid in the permanganate bleach calls for 10ml of conscentrated sulphuric acid in 1000ml total solution (10+990).
It seems I'd need 72ml of 5N sulfuric acid, right?

Rudeofus · Aug 30, 2024

1M H2SO4 is 1 mol of H2SO4 per liter. However, since H2SO4 has two easily removable protons, a 1M solution (98 g/l) would be 2N.

If you start with concentrated Sulfuric Acid, that would be 18M (or 36N).

revdoc · Aug 30, 2024

You can also use sodium bisulfate, which is sold to lower pH in swimming pools, and might be easier to get. E.g., here:

Subsitution of Sodium bisulfate for Sulfuric acid - w/v calculation query

Most threads asking about this seem to end up with the advice "you can buy Sulfuric acid at the auto store" being repeated several times, but I'm asking a very specific question and thus the former is not going to be a helpful answer ;) We know we can substitute Sodium bisulfate for Sulfuric...

www.photrio.com

I use this for reversal processing lith film. (Note: it's bisulfate, not bisulfite.)

DeletedAcct1 · Aug 30, 2024

revdoc said:
You can also use sodium bisulfate, which is sold to lower pH in swimming pools, and might be easier to get. E.g., here:

Subsitution of Sodium bisulfate for Sulfuric acid - w/v calculation query

Most threads asking about this seem to end up with the advice "you can buy Sulfuric acid at the auto store" being repeated several times, but I'm asking a very specific question and thus the former is not going to be a helpful answer ;) We know we can substitute Sodium bisulfate for Sulfuric...

www.photrio.com

I use this for reversal processing lith film. (Note: it's bisulfate, not bisulfite.)

Over the years I've found that it's fundamental the purity grade of Sodium bisulfate. Technical grade can have some chlorine in it, sufficiently high to render the bleach a rehalogenating bleach unsuitable for b&w processing.
However thanks for the suggestion.

fgorga · Aug 30, 2024

Alessandro Serrao said:
My bad, I mean what 5N equals % in weight?
The acid in the permanganate bleach calls for 10ml of conscentrated sulphuric acid in 1000ml total solution (10+990).
It seems I'd need 72ml of 5N sulfuric acid, right?

72 mL is correct.

Just remember that the total volume should remain 1000 mL, so you would use 72 mL + 918 mL

MattKing · Aug 31, 2024

fgorga said:
72 mL is correct.

Just remember that the total volume should remain 1000 mL, so you would use 72 mL + 918 mL

Or even better, 72 ml + 928 ml .

fgorga · Aug 31, 2024

MattKing said:
Or even better, 72 ml + 928 ml .

Arrrgh! My aging brain can't even do simple arithmetic anymore. I guess that I'll have to get one of those newfangled calculator thingies!

BobUK · Aug 31, 2024

fgorga said:
Arrrgh! My aging brain can't even do simple arithmetic anymore. I guess that I'll have to get one of those newfangled calculator thingies!

Depending upon your age, they are called parents or grandchildren.

I am going to scribble the maths of this into my book of facts. I need Sulphuric Acid to try out the Bromoil process.
Thank you.

john_s · Aug 31, 2024

fgorga said:
Arrrgh! My aging brain can't even do simple arithmetic anymore. I guess that I'll have to get one of those newfangled calculator thingies!

I remember years ago doing first year maths at university that an esteemed lecturer in a lecture couldn't do simple arithmetic on the blackboard with simple small integers. He was apparently quite brilliant in his field.

lamerko · Sep 3, 2024

Concentrated sulfuric acid is nasty, and it is absolutely prohibited to sell it to private individuals. 5N sulfuric acid is also prohibited in my region. Separately - it is quite expensive, I don't know for what reason. But you can easily buy battery acid that is around 37%. Not very accurate, but enough. There are some unknowns, but it can roughly equate to about 10N. Therefore, if you have such an acid, you can use 27-30 ml. It will be around the tolerance limits.

Sulfuric acid 5N

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