calculating pH of sulfuric acid (1 Viewer)

[mr_guy99493]

i know how to calculate the pH of HCl etc, but sulfuric acid is diprotic....
cant rememeber exactly what happens, but, after the first ionisation, isnt hso4- an extremely weak base.... conjugate base thing? or does that second H ionise too, to make a nice happy situation.

 

[persephone]

all i know is that for sulfuric acid you double the hydrogen ion concentration and then put that into the formula thing

 

[helper]

Same way as HCl but double the hydrogen ion concentration before calculating the pH.

 

[aim54x]

helper is right double the H+ conc. this is wat the txt says

 

[paganinio]

sulfuric acid has 2 H and HCl has only 1. That's the only difference.

 

[JamiL]

HSO4- is a strong acid as far as i know

 

[xiao1985]

HSO4- is a strong acid as far as i know

sorry to dissapoint u, but hso4 - is a weak acid...

sulfuric acid ionises in two steps, first step is strong, second step is weak... but as far as hsc is concerned, if you are not told that 2nd step is wk, and u are asked to calculate pH, u can assume 2nd step is strong...

i tend to make a note of my assumption tho... say s.th. like assuming 2nd step of ionising is strong as well...

 

[Xayma]

HSO4- is a strong acid as far as i know

No acid is strong on more then their first ionisation.

 

[xiao1985]

No acid is strong on more then their first ionisation.

agreed......

 

[Xayma]

Well there aren't that many strong acids anyway:

Hydrobromic Acid
Hydrochloric Acid
Hydroiodide Acid
Sulfuric Acid
Nitric Acid
Perchloric Acid

Which as far as the HSC is concerned are all the same strength (being strong acids) but they do have different strengths, but you need to consider different solvents to find them.

Of them only sulfuric acid is diprotic or greater.

 

[nit]

hmm..resurrecting a fairly old thread i guess. Anyway, sulfuric acid is one of the strongest acids. bisulfate anion has pKa of 1.92 or something like that, which isn't too bad for a second deprotonation step.

 

[xiao1985]

hmm..resurrecting a fairly old thread i guess. Anyway, sulfuric acid is one of the strongest acids. bisulfate anion has pKa of 1.92 or something like that, which isn't too bad for a second deprotonation step.

OMG 1.92??? that can well be said as a strong acid...