All Questions
84
questions
15
votes
1
answer
8k
views
Calculating the pH of a highly dilute solution of HCl
For relatively high concentrations of $\ce{HCl}$, I usually just assume that $[\ce{H+}] = [\ce{HCl}]$, because $\ce{HCl}$ is a strong acid and is completely ionized in solution. By taking the negative ...
- 1,128
45
votes
4
answers
53k
views
The reason behind the steep rise in pH in the acid base titration curve
Most books refer to a steep rise in pH when a titration reaches the equivalence point. However, I do not understand why … I mean I am adding the same drops of acid to the alkali but just as I near the ...
- 2,423
125
votes
7
answers
87k
views
Is a negative pH level physically possible?
A friend of mine was looking over the definition of pH and was wondering if it is possible to have a negative pH. From the equation below, it certainly seems mathematically possible—if you have a $1.1$...
- 1,369
32
votes
2
answers
35k
views
What is the pKa of the hydronium, or oxonium, ion (H3O+)?
Although the wikipedia page on Hydronium indicates a $\mathrm{p}K_\text{a}$ of −1.74, I noticed in the discussion of this page that the subject seems debated (cf. http://en.wikipedia.org/wiki/Talk:...
- 597
9
votes
3
answers
6k
views
The pH of a neutralized solution
If pH is defined as the concentration of hydrogen ions in solution, then how can a ���neutralized’ solution (defined as having an equal amount of hydrogen and hydroxide ions) have a pH other than 7?
...
- 209
21
votes
3
answers
17k
views
Does the number of H+ ions in solution go up on dilution of a weak acid?
In my textbook, a footnote says:
In case of weak acids, on dilution the total number of $\ce{H^{+}}$ ions in solution increases because dissociation of the weak acid increases
This didn't make ...
- 3,479
15
votes
4
answers
71k
views
Shouldn't the pH at the equivalence point always be 7?
I learned in class that the equivalence point in an acid-base titration is reached when the solution contains an equal amount of substance of $\ce{OH-}$ and $\ce{H+}$ ions. However, in a weak acid and ...
- 2,423
7
votes
3
answers
49k
views
pH range outside conventional 0-14 [duplicate]
Is a pH value outside 0 - 14 possible?
I asked my teacher who said: yes, it is, but very difficult to achieve.
Then on the internet, I found multiple answers, one saying it is but because of a fault ...
- 335
5
votes
2
answers
26k
views
Why will a strong acid neutralize as much base as a weak acid?
This is a simple concept that I can't seem to understand. Why will a strong acid neutralize as much base as a weak acid, if the acids are of the same volume and concentration? A strong acid will ...
- 245
17
votes
1
answer
17k
views
How does the litmus pH indicator work?
I'm wondering about how does the litmus solution work as a pH indicator.
And another question:
When you put drops of litmus solution into an colorless acid (e.g. $\ce{HCl}$), it turns red. But then ...
- 391
14
votes
2
answers
169k
views
What are the products of the dissociation of sodium bicarbonate in water? What is the relative pH of the solution?
I had a recent question on a test that asked what the products would be if sodium hydrogen carbonate were dissolved in water. I had a few candidate answers
$\displaystyle\ce{NaHCO3 -> Na+ + HCO3-}$...
- 371
12
votes
5
answers
41k
views
How to determine the pH of a mixture of two weak acids?
We have two solutions:
Solution 1 is $\ce{HCOOH}$, its concentration is $c_1 = \pu{10^-2 mol/l}$, its volume is $V_1 = \pu{50 ml}$, and its $\mathrm{pH}_1 = 2.9$.
Solution 2 is $\ce{CH3COOH}$, its ...
- 121
7
votes
2
answers
43k
views
Why is a buffer solution best when pH = pKa i.e. when A-/HA=1
Buffers work best when $\mathrm{pH}$=$\mathrm{p}K_\mathrm{a}$
From the Henderson-Hasselbalch equation,
$\mathrm{pH}= \mathrm{p}K_\mathrm{a} + \log_{10}\left(\frac{[\ce{A-}]}{[\ce{HA}]}\right)$
If $...
- 2,853
2
votes
2
answers
2k
views
How concentrated can an acid be?
How concentrated can an acid be without it being supersaturated? Is there a certain limit to how concentrated an acid or base can be?
When I mean concentration, I mean molarity; so how concentrated ...
- 3,050
2
votes
1
answer
1k
views
Chalcogens' hydrides as acids?
I've noticed that chalcogens never form binary acids, and instead end up like water, with very little acidity. Why is this? Or am I wrong and there's a counterexample, if so please give it.
- 957