I'm sure this has been asked N_A times, but I haven't been able to find a clear answer -- just bits and pieces as parts of larger discussions. My chemistry classes are many years in the past now, so I might not even be asking sensible questions. However..

 

I'm looking for formulae relating concentrations, pH, and molarity to each other, for strong acids/bases. For example, I have here a bottle of industrial H₂SO₄ for which the MSDS claims the 'Hazardous Components: Sulfuric Acid 93.2%'. Is it safe to assume that's w/w? Presuming the other 6.8% is water, how can I determine the molarity and pH?

 

Thanks in advance..

I finally managed to phrase my search in such a way as to find something useful: http://www.chembuddy.com/?left=concentration-questions&right=mass-percentage-to-molarity-q1. Given that, and the best MSDS I could find for this bottle of Rooto drain opener, and assuming the solvent is H₂O, and that the figures on the ChemBuddy site are accurate, and linearly interpolating the density of 93.2% H₂SO₄, I get this:

 

m[sub]H[sub]2[/sub]SO[sub]4[/sub][/sub] = 98.07848
d[sub]H[sub]2[/sub]SO[sub]4[/sub][/sub] = 1.821761 (interpolated)
c[sub]M[sub]H[sub]2[/sub]SO[sub]4[/sub][/sub][/sub] = (10 × 93.2 × 1.821761) ÷ 98.07848
     = 17.3114537

 

The only figure there that's accurate is the molar mass of H₂SO₄; the density is interpolated from a w/w concentration that may or may not be accurate.

 

However, the result of approximately 17 molar seems about right to me.

 

Did I do this correctly, or did I screw up somewhere?

 

Now on to figuring out the pH..

I have a slightly higher value for the density, but otherwise you are right on track.

Sounds right. Now If you want a hint I suggest you look up formulas for finding the pH of diprotic acids.