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

[pdeeh]

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 acid (in, for example, silver bleaches), but I've been hard pressed to find a verified w/v formula for doing so.

I'm sure if I understood moles and whatnot I could work it out myself, but as I don't, I can't ... hence the question.

After a bit of digging around I found (there was a url link here which no longer exists) in (there was a url link here which no longer exists).

In that post, it is suggested that 4.3g of anhydrous bisulfate (or ~5g monohydrate) is equivalent to 1ml of concentrated Sulfuric acid.

From that, I have inferred that if I want 1000ml equivalent of (say) a 10% solution of Sulfuric acid in water, then I would require 430g of Sodium bisulfate dissolved in 1000ml of water (or 500g in 1000ml if the bisulfate is in monohydrate form).

(This is "for all practical purposes" rather than scientific exactitude)

If this post catches the eye of one of our resident chemists, could they confirm (or correct) the substitution ratio(s)?

thanks in advance

 

[Gerald C Koch]

One mole of sodium bisulfate produces the same number of hydrogen ions as one mole of sulfuric acid. For every gram of concentrated sulfuric acid or equivalent substitute 2.40 grams of anhydrous sodium bisulfate. If the recipe calls for concentrated sulfuric acid then 1 ml of acid weighs 1.84 grams. Therefore for 1 ml of concentrated acid substitute 4.42 grams of anhydrous sodium bisulfate.

 

[RPC]

So does this mean that one can use sodium bisulfate to adjust the pH of color developers in place of sulfuric acid? Can sodium bisulfite be used?

 

[pdeeh]

One mole of sodium bisulfate produces the same number of hydrogen ions as one mole of sulfuric acid. For every gram of concentrated sulfuric acid or equivalent substitute 2.40 grams of anhydrous sodium bisulfate. If the recipe calls for concentrated sulfuric acid then 1 ml of acid weighs 1.84 grams. Therefore for 1 ml of concentrated acid substitute 4.42 grams of anhydrous sodium bisulfate.

excellent.

thank you Gerald

 

[Gerald C Koch]

So does this mean that one can use sodium bisulfate to adjust the pH of color developers in place of sulfuric acid? Can sodium bisulfite be used?

NO Sodium bisulfite is a reducing agent and can cause all sorts of problems with color developers.

 

[Gerald C Koch]

CORRECTION

The first sentence of my original post should read "Two moles of sodium bisulfate ..." instead of "One mole of sodium bisulfate... ." The sentence was a last minute addition that slipped by the proofreader (me). The calculations are however correct. I apologize if there was any confusion.

 

[pdeeh]

Noted

 

[gzinsel]

no; "duly" noted!