[peterpan1372]

Hello,

I have a question regarding the picture...
I know the formula: V1*M1*n2=V2*M2*n1

my only question is: how can I know n1 and n2?

[Borek]

What are n1 and n2?

[peterpan1372]

n1 and n2 are the number of molecules...

[Borek]

Number of molecules in what?

[peterpan1372]

n1=NaOH
n2=diprotic acid...

[Borek]

Assume any diprotic acid, can you predict with how many molecules of NaOH will one molecule of such acid react?

[peterpan1372]

well, diprotic (as the name says) has 2protons. since NaOH has only one H molecule, there must be two NaOH, or?

[Borek]

well, diprotic (as the name says) has 2protons

Yes.

since NaOH has only one H molecule

No, NaOH doesn't have one H molecule. If anything, it has one H atom per NaOH molecule. Which is not that important, as H from the NaOH doesn't take part in neutralization.

Can you write reaction equation of a neutralization reaction between - say - NaOH and HCl?

there must be two NaOH, or?

Miraculously, that's correct.

[peterpan1372]

NaOH + HCl -> NaCl + H2O

[Borek]

NaOH + HCl -> NaCl + H2O

So it is not H of NaOH, but some other part of the molecule that reacts during the neutralization, isn't it?

As you got correct values of n1 and n2 question is solved.

In general whenever dealing with titration it is always about reaction equation and stoichiometry:

http://www.titrations.info/titration-calculation

[Arkcon]

NaOH + HCl -> NaCl + H2O

Good start.  Now, ignore your formula, V1*M1*n2=V2*M2*n1, please.  Although you may like it, and may have been taught it, you don't seem to really understand it.

Now, working with the actual problem:

What volume of 0.10 M NaOH is needed to neutralize 30 mL of 0.20 M of the diprotic acid H₂(random anionate).

Look and see what I've done:

1). First of all, I wrote it down, instead of taking a picture with my phone, this gives a person a chance to study a problem, to be sure they understand it.
2).  I changed the units.  If you don't like that or don't understand that, no problem.  You can use your oid units, if you want to keep writing them.
3).  They say diprotic acid, but they don't say which one.  No matter, I made up a diprotic acid.  I could have called it H₂(peterpanate).  Notice though:  they said diprotic, and you used a monoprotic acid as an example.  Sorry, but your phone wasn't able to help you, whereas writing it down would.  Please don't use HCl as an example again, for this problem, it just means that you won't read our help, and just want the answer given to you.

OK, lets try changing units again, to see if you have something to visualize:

You have a two stacks of 30 copper coins.  You have to make stacks of coins, one silver coin, with one copper coin.  How many silver coins do you need?

[peterpan1372]

60?

[Borek]

they said diprotic, and you used a monoprotic acid as an example

I asked to use HCl as an example of neutralization, not as a part of solving the problem, so don't blame OP

[peterpan1372]

they said diprotic, and you used a monoprotic acid as an example

I asked to use HCl as an example of neutralization, not as a part of solving the problem, so don't blame OP

I still dont know why there are two molecules NaOH and one H2...

[Borek]

I still dont know why there are two molecules NaOH and one H2...

There is no H₂ there.

Do you know what acids are? What bases are? How do they react? Sorry, we are not going to teach you everything from scratch and it looks like your problems stem from the fact you have not covered the most basic subjects. You need to go back and work from the beginning.