What is the pH of a solution formed when 100 mL of an acid wirh a pH of 2 is diluted to liter with pure water?

a.) 1
b.) 2
c.) 3
d.) 5

Question

What is the pH of a solution formed when 100 mL of an acid wirh a pH of 2 is diluted to liter with pure water?  

a.) 1 
b.) 2 
c.) 3 
d.) 5

e.cociuba · Answer

@Lexusiesha @IanK16. @jeanettecrisman @electrokid @dellzasaur @katieecrowleyy

e.cociuba · Answer

Can anyone help?

anonymous · Answer

i think that it is D. 5

e.cociuba · Answer

Can u explain?

anonymous · Answer

it is a guess

anonymous · Answer

You know the pH of pure water is very close to 7, right?

e.cociuba · Answer

Yes because pure water is basically neutral.

anonymous · Answer

So you can cross out a and b.

anonymous · Answer

it is ether C or D then

e.cociuba · Answer

Yes, but can't u solve this using a formula to make sure it's correct?

e.cociuba · Answer

Ok I'm so confusing myself now....

e.cociuba · Answer

My professor said this one would be a challenge and I guess it is...

anonymous · Answer

Do you remember the definition of pH?

e.cociuba · Answer

pH: it's something tht expresses the acidity of a solution on a logarithmic scale.

anonymous · Answer

pH = 2 means there are 0.01 moles of H+ in a litre.
pH = 3 means there are 0.001 moles of H+ in a litre.
So how many moles of H+ do you think there are in a litre of water?

e.cociuba · Answer

I don't no....Ur confusing me, I think this is supposed to have a formula tht helps u solve it..

e.cociuba · Answer

I thought I was suppoed to use one of theses solutions: 

1.) pH= =log [H+] 
           OR 
2.) [H+] [OH-]= 1.0 x 10^-14 ??

anonymous · Answer

pH is related to the mole density of H+. The higher the pH, the lower the H+ molar density. You need to use the solution 1: pH = log [H+].

anonymous · Answer

From that relation, you know pH 7 means [H+] = 0.0000001 mol/l.

e.cociuba · Answer

Ok so I would do pH= =log [1 x 10^-2] but I don't no wat to do after..

anonymous · Answer

To get a litre of solution, you need 900 ml of water, right? Because you've got to use 100 ml of pH 2 acid.

e.cociuba · Answer

I'm officially confused and think I'm done w/ this problem.

anonymous · Answer

im not good with chem so i rly cnt help, sorry

anonymous · Answer

Ok. The answer is c.

e.cociuba · Answer

it's kool :)

e.cociuba · Answer

But I don't want the answer, I want to no how to slove it..

anonymous · Answer

What you basically have to do is to work out how many moles of H+ there are in 100 ml of the acid and 900 ml of water. Then you know how many moles of H+ there are in the solution by adding them up, then you can use pH = log [H+] to get the answer.

e.cociuba · Answer

Ok well um thanks I guess. :)

anonymous · Answer

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