eeek (1 Viewer)

[Maddy1012]

In this dot point book for chem it has questions like

What is the pH for 0.01 of Sulfuric acid and its answer is 0.7... i thought it would be ph of 2.
When you apply -log [h+] it doesnt work.
Would they ask questions like that in the exam or will they always give u questions where you just apply -log [h+]

anyone help me

and how do you do ones where its like

calculate the pH when only 8% is ionised?

 

[Martyno1]

Because sulphuric acid is diprotic, it has two ionisations, when you worked out the pH you only counted one. The theoretical pH would be -log 0.02, but I'm not sure if that is the actual pH of 0.01 mol/L sulphuric acid.

With the 8% thing, do you have an example of a question?

 

[undalay]

In this dot point book for chem it has questions like

What is the pH for 0.01 of Sulfuric acid and its answer is 0.7... i thought it would be ph of 2.
When you apply -log [h+] it doesnt work.
Would they ask questions like that in the exam or will they always give u questions where you just apply -log [h+]

anyone help me

and how do you do ones where its like

calculate the pH when only 8% is ionised?

0.7 or 1.7?

 

[Maddy1012]

0.7 or 1.7?

0.7 i know im stumped aswell.

 

[wrxsti]

answers are clearly wrong....

 

[undalay]

0.7 i know im stumped aswell.

What does the question ask, exactly ? word for word?

 

[Mattamz]

for the 8% ionisation does anyone agree that it would be

pH = -log{[H+]*(8/100)}

 

[Martyno1]

for the 8% ionisation does anyone agree that it would be

pH = -log{[H+]*(8/100)}

Yes, well that's what I'd do.

 

[jlnWind]

answers are clearly wrong....

Yeh its clear that the answers are wrong.
-log[0.02] = 1.69 (i.e. 1.7) they've mistyped it for sure

And its a bad question from the start because as marty said
its diprotic meaning there are two equations for the ionisation of H2SO4
i) H2SO4 + H2O --> H3O(+) + HSO4(-)
ii) HSO4- + H2O <--> H3O(+) + SO4(2-)