Last minute pH and buffer questions~~

[chaser0]

---

Members don't see this ad.

I had a last few questions before I head to bed~


Does water change the pH of buffer solutions?
Does strong acids/Bases such as HCl or KNH2 change the pH of buffer solutions?

Finally,
How are strong acid/base solutions affected by an alteration in pH compared to weak acid/base solutions? (I heard that strong acids/bases are not at all affected by pH variations)

 

[loveoforganic]

No. (HH equation)

Yes. (HH equation again)

This question doesn't really make sense. The solution of strong/weak acid/base is what gives rise to the pH.

 

[coyfish]

I had a last few questions before I head to bed~


Does water change the pH of buffer solutions?
Does strong acids/Bases such as HCl or KNH2 change the pH of buffer solutions?

Finally,
How are strong acid/base solutions affected by an alteration in pH compared to weak acid/base solutions? (I heard that strong acids/bases are not at all affected by pH variations)

I think with the last question you are talking about titration where you add drops of acid/base to adjust the pH of a solution. If you have a "large" basic solution it is going to take more drops of acid to start lowering the pH than a small quantity of solution. Once you have enough however the pH may change significantly with only one drop until the same condition (only acidic) is reached. Then it will take more drops to make dramatic change.

 

[Rayhaan]

Water dilutes but does not change the RATIO of acid to base. So the buffering isn't affected.

For your second question I am not sure what you are asking but I will take a stab.

Weak acid or weak base neutralizations are affected by pH in the sense that their equivalence pH will change depending on how strong the weak acid/base really is. The stronger it is the closer the equivalence will be to the original pH of the acid or base.

Strong acid/base neutralizations do not have their equivalence changed as it is going to be at 7. However, the amount of titrant added would need to change as the equivalence is simply the point where moles H = moles OH. If the pH of the acid was lower (more H), you would need to add more base.