Comparing pH of HBrO4 and HIO3

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In summary: The prefixes "meta-" and "para-" indicate that the acid is in a higher or lower oxidation state, respectively. In the context of naming chemicals, they indicate that the acid is meta- or para-periodic.
  • #1
bomba923
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Which is stronger (lower pH): [tex] {\text{HBrO}}_{\text{4}} [/tex] or [tex] {\text{HIO}}_{\text{3}} [/tex] ?

How would I name [tex] {\text{HIO}}_{\text{4}} [/tex]-- Periodic acid, I suppose?

If perchoric acid is [tex] {\text{HClO}}_{\text{4}} [/tex], why then is periodic (per-iodic) acid [tex] {\text{H}}_{\text{5}} {\text{IO}}_{\text{6}} [/tex] ? ( as on http://chemistry.about.com/cs/molecules/a/blperacid.htm )

Why does http://chemistry.about.com/cs/molecules/a/blperacid.htm and http://www.gfschemicals.com/chemicals/gfschem-74.asp say that periodic acid is [tex] {\text{H}}_{\text{5}} {\text{IO}}_{\text{6}} [/tex] , but http://www.online-medical-dictionary.org/?q=Periodic+Acid+(HIO4) and http://www.catalogue.fisher.co.uk/scripts/search.dll?ViewMSDS&SheetNumber=19510 say that periodic acid is [tex] {\text{HIO}}_{\text{4}} [/tex] ?

(I suppose [tex] {\text{HIO}}_{\text{4}} [/tex] is metaperiodic acid, then?)

Finally, (it will be strong, no doubt, but) just how strong exactly would [tex] {\text{HIO}}_{\text{4}} [/tex] be? (Safety Description (please)--cannot locate on web)
 
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  • #2
For the terminology question,i think IUPAC gave clear rules...Look for them.

Daniel.
 
  • #3
bomba923 said:
Which is stronger (lower pH): [tex] {\text{HBrO}}_{\text{4}} [/tex] or [tex] {\text{HIO}}_{\text{3}} [/tex] ?

How would I name [tex] {\text{HIO}}_{\text{4}} [/tex]-- Periodic acid, I suppose?

If perchoric acid is [tex] {\text{HClO}}_{\text{4}} [/tex], why then is periodic (per-iodic) acid [tex] {\text{H}}_{\text{5}} {\text{IO}}_{\text{6}} [/tex] ? ( as on [/QUOTE] Did you mean or [tex] {...e not the number of water molecules involved.
 
  • #4
DrMark said:
Did you mean or [tex] {\text{HIO}}_{\text{3}} [/tex] or [tex] {\text{HIO}}_{\text{4}} [/tex]

No--Actually, I wanted to see which would be most significant. The iodine with the oxygens in [tex] {\text{HIO}}_{\text{3}} [/tex] greatly shifts electron density away from the hydrogen.
In [tex] {\text{HBrO}}_{\text{4}} [/tex], the same thing happens. However, we have a lighter halide with few electrons---but more oxygen attached to it!

Basically, what is more important: mass of the halide (molar mass, atomic number (more electrons means more electron density away from acidic hydrogen))...or, the number of oxygen attached to the halide?

Bromine is lighter than iodine, but has one more oxygen attached to it. In a test of acid strength, which would win: [tex] {\text{HIO}}_{\text{3}} [/tex] or [tex] {\text{HBrO}}_{\text{4}} [/tex] ?

(But as for my other question, IUPAC says periodic acid is [tex] {\text{HIO}}_{\text{4}} [/tex] , but many websites seem to differ tho...)
 
  • #5
bomba923 said:
No--Actually, I wanted to see which would be most significant. The iodine with the oxygens in [tex] {\text{HIO}}_{\text{3}} [/tex] greatly shifts electron density away from the hydrogen.
In [tex] {\text{HBrO}}_{\text{4}} [/tex], the same thing happens. However, we have a lighter halide with few electrons---but more oxygen attached to it!

Basically, what is more important: mass of the halide (molar mass, atomic number (more electrons means more electron density away from acidic hydrogen))...or, the number of oxygen attached to the halide?

Bromine is lighter than iodine, but has one more oxygen attached to it. In a test of acid strength, which would win: [tex] {\text{HIO}}_{\text{3}} [/tex] or [tex] {\text{HBrO}}_{\text{4}} [/tex] ?

(But as for my other question, IUPAC says periodic acid is [tex] {\text{HIO}}_{\text{4}} [/tex] , but many websites seem to differ tho...)

Actually H5IO6 should be written as HIO4.2H2O.
The pKa of HBrO3 is -1.0 while that of HIO3 is .74 so yes HBrO4 is likely the stronger acid (couldn't find numbers on HBrO4). HBrO4 is in higher oxidation state (the halide that is) and has greater electronegativity, hence it should be the stronger acid.
 
  • #7
Paraperiodic being [itex] H_{5}IO_{6} [/itex] ? Highly unlikely.U need to compare the first acidity constant of both acids (actually,monoprotic acids have only one).

Daniel.
 
  • #8
Yes--Paraperiodic acid is a weak polyprotic acid

But one more question tho:
In the context of naming chemicals, what do the prefixes "meta-" and "para-" indicate?
 
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  • #9
I think/hope it's clear for organic substances...(look for "benzene cycle").

As for inorganic,well,i'll let someone else more knowledgeable do the talking.

Daniel.
 

Q1: What is the chemical formula for HBrO4 and HIO3?

HBrO4 stands for Hydrogen Bromate and has a chemical formula of HBrO4. HIO3 stands for Iodic Acid and has a chemical formula of HIO3.

Q2: How do the pH values of HBrO4 and HIO3 compare?

The pH values of HBrO4 and HIO3 are both acidic, but the pH of HBrO4 is generally lower than that of HIO3.

Q3: What factors affect the pH of HBrO4 and HIO3?

The pH of HBrO4 and HIO3 is affected by the concentration of the solutions, temperature, and any other substances present in the solution.

Q4: What is the relationship between pH and acidity?

pH is a measure of the acidity of a solution. The lower the pH, the more acidic the solution is, while a higher pH indicates a more basic solution.

Q5: Why is it important to compare the pH of HBrO4 and HIO3?

Comparing the pH of HBrO4 and HIO3 can provide insight into the strength and reactivity of these acids, which is important in various scientific and industrial applications.

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