Calculating pH of a Monoacidic Base Solution in Water

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The discussion focuses on calculating the pH of a monoacidic base solution in water, specifically addressing the confusion around the term "monoacidic base" and its implications for pH calculations. Participants clarify that a monoacidic base, represented as MOH, generates one mole of OH- ions per mole of base dissolved. The correct approach involves calculating pOH as -log[OH-], followed by deriving pH using the relationship pH = 14 - pOH. The conversation highlights the importance of understanding the mole concept and the water ion product in these calculations. Ultimately, the thread concludes with a reminder of key formulas related to pH and pOH for future reference.
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Homework Statement


x mole of a strong monoacidic base is dissolved in one litre of water. The pH of the solution will be
(a)-log x
(b)14-log x
(c)14+log x
(d)-log (14-x)


Homework Equations





The Attempt at a Solution



For instance i assumed that the base is NaOH but it does not react with water to form any compound. So i am confused how should i start?

Thanks! :smile:
 
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I'm still working on "monoacidic base"...
What's that?

OK. I just Googled it. So you have a base that generates 1 mole of OH- per mole of base in water. You also know the following:
1) pH = -log[H+]
2) [H+][OH-] = 1.01 X 10-14

Can you get it from there?
 
Last edited:
First calculate the pOH, which equals to -log[OH-].
Then, pH=14-pOH. That's it.
 
chemisttree said:
I'm still working on "monoacidic base"...
What's that?

OK. I just Googled it. So you have a base that generates 1 mole of OH- per mole of base in water. You also know the following:
1) pH = -log[H+]
2) [H+][OH-] = 1.01 X 10-14

Can you get it from there?

I think it isn't stated that it generates one mole of OH-. :smile:
 
Pranav-Arora said:
I think it isn't stated that it generates one mole of OH-. :smile:

Monoacidic base is written in the form of MOH where M is any univalent metal.

Hints :
1 mole of MOH in water furnishes one OH- ion.
Then x moles of MOH will furnish... ?

Write an ionic equation in terms of "x" and think about Mole Concept once again. You can then use the formulas given by chemisttree.
 
Last edited:
sankalpmittal said:
think about Gay Lussac's law and Avogadro's law.

Huh? What do the laws concerning gases have to do with the pH of the solution?
 
This isn't a hard question as i thought of and thanks to chemistree for the idea of pOH.

I found out the pOH which is -log x. Then calculated pH, which is completely easy pH=14-pH.

@sankalp:- I think i am not that bad at chemistry that you need to remind me of Mole concept.

I just forgot to reply in this thread after solving the problem. :P
 

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