URGENT - Question on pH calculation (1 Viewer)

[JoshyPutts07]

Does anyone know how to find the pH of completely ionized sulfuric acid

it is a multiple choice question and i keep getting the answer of 3.82 where the real answer is 3.5 and i dont know why

the values are 1.5x10(to the negative four)

you throw it into a log and it spits a 3.82 not a 3.5?

it must be something to do with the complete ionization right? BUT WHAT!?

please help

 

[JoshyPutts07]

Does anyone know how to find the pH of completely ionized sulfuric acid

it is a multiple choice question and i keep getting the answer of 3.82 where the real answer is 3.5 and i dont know why

the values are 1.5x10(to the negative four)

you throw it into a log and it spits a 3.82 not a 3.5?

it must be something to do with the complete ionization right? BUT WHAT!?

please help

Don't worry got it, It is because sulfuric acid is a diprotic acid not a monoprotic acid so you have to times the concentration by two then punch that value into the log...................VOILA...........how silly of me

 

[wrxsti]

lol...... try this question... if you can do this you can do any PH question...

Question: Find PH of 5x10^-5 Molarity Magnesium Hydroxide Solution

Its a pretty good question

 

[xiao1985]

if i got this right, Mg hydroxide isn't soluable in water, dear wrxsti =p

presuming it is, 10?! at STP of course

 

[Queen Llamah]

Does anyone know how to find the pH of completely ionized sulfuric acid

it is a multiple choice question and i keep getting the answer of 3.82 where the real answer is 3.5 and i dont know why

the values are 1.5x10(to the negative four)

you throw it into a log and it spits a 3.82 not a 3.5?

it must be something to do with the complete ionization right? BUT WHAT!?

please help

H₂SO₄
Sulfuric acid is a diprotic acid, (TWO HYDROGENS) so when calculating the pH we go;

pH= -log(1.5x10^-4x2)
which gives you, pH= 3.5228745.........

I hope that helps

REMEMBER, when a acid is Diprotic it has 2 hydrogens so in the brackets of the calculation it needs to be mulitipled by 2.

 

[xiao1985]

now, something not needed to know in HSC: first step of ionisation is complete, but 2nd is not...

so the pH of this sulfuric acid solution will be between 3.52 and 3.82