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Topic: Neutralization  (Read 4315 times)

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Offline peterpan1372

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Neutralization
« on: September 14, 2017, 03:58:15 PM »
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?


Offline Borek

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Re: Neutralization
« Reply #1 on: September 15, 2017, 04:14:17 AM »
What are n1 and n2?
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Offline peterpan1372

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Re: Neutralization
« Reply #2 on: September 15, 2017, 05:17:43 AM »
n1 and n2 are the number of molecules...

Offline Borek

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Re: Neutralization
« Reply #3 on: September 15, 2017, 05:43:56 AM »
Number of molecules in what?
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Offline peterpan1372

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Re: Neutralization
« Reply #4 on: September 15, 2017, 05:49:21 AM »
n1=NaOH
n2=diprotic acid...

Offline Borek

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Re: Neutralization
« Reply #5 on: September 15, 2017, 06:21:29 AM »
Assume any diprotic acid, can you predict with how many molecules of NaOH will one molecule of such acid react?
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Offline peterpan1372

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Re: Neutralization
« Reply #6 on: September 15, 2017, 06:55:22 AM »
well, diprotic (as the name says) has 2protons. since NaOH has only one H molecule, there must be two NaOH, or?

Offline Borek

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Re: Neutralization
« Reply #7 on: September 15, 2017, 07:53:04 AM »
well, diprotic (as the name says) has 2protons

Yes.

Quote
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?

Quote
there must be two NaOH, or?

Miraculously, that's correct.
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Offline peterpan1372

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Re: Neutralization
« Reply #8 on: September 15, 2017, 08:23:17 AM »
NaOH + HCl -> NaCl + H2O

Offline Borek

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Re: Neutralization
« Reply #9 on: September 15, 2017, 09:21:59 AM »
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
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Offline Arkcon

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Re: Neutralization
« Reply #10 on: September 15, 2017, 10:23:17 AM »
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?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline peterpan1372

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Re: Neutralization
« Reply #11 on: September 15, 2017, 10:26:26 AM »
60?

Offline Borek

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Re: Neutralization
« Reply #12 on: September 15, 2017, 11:04:06 AM »
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 :)
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Offline peterpan1372

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Re: Neutralization
« Reply #13 on: September 15, 2017, 11:10:19 AM »
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...

Offline Borek

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Re: Neutralization
« Reply #14 on: September 15, 2017, 12:46:46 PM »
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.
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