All Questions
Tagged with equilibrium ph
139
questions
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
25
votes
2
answers
13k
views
Why does water dissociate to H3O+ and OH- rather than H+ and OH-?
Why does water dissociate to
$\ce{H3O+ + OH-}$
instead of $\ce{H+ + OH-}$?
This question came to surface when I was learning about acids and bases, and learned this definition:
$\mathrm{pH=}-\log_{10}[...
- 383
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
21k
views
Is LiOH a weaker base than NaOH?
Is $\ce{LiOH}$ a weaker base than $\ce{NaOH}$?
Note: I'm not interested in "why," but rather what the "real" $\mathrm{p}K_
\mathrm{b}$ values are.
$$
\begin{array}{lcc}
\text{Data for Alkali Metal ...
- 22.3k
13
votes
1
answer
18k
views
Effect of Temperature on pH of Water
The $K_\mathrm w$ is a function of temperature. It is $10^{-14}$ at $25\ \mathrm{^\circ C}$. When the temperature is $50\ \mathrm{^\circ C}$, the $K_\mathrm w$ can be calculated to be somewhere around ...
- 435
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
10
votes
5
answers
50k
views
What's the pH of vinegar containg 5% acetic acid?
Vinegar generally contains 5% acetic acid. We would expect the pH of vinegar to be approximately:
a. 0
b. 3
c. 7
d. 9
e. 12
I don't have the key for this question, so I just want to make ...
- 3,050
9
votes
2
answers
959
views
Numerically solving chemical equilibrium equations
Here are chemical equilibrium equations:
$\begin{cases}
\mathbf{N}^\text{T}\mathbf{X}+\mathbf{C}=\mathbf{Y}\\
\mathbf{N}\ln\mathbf{Y}=\ln\mathbf{K}
\end{cases}$
Here $\mathbf{C}=\begin{pmatrix}c_1\\...
- 219
9
votes
1
answer
3k
views
Why is it that weak bases usually contain nitrogen?
Why do weak bases usually contain nitrogen? I know there are two electrons on top for a bond of $\ce{H}$ but why is it mostly nitrogen? I know there are other elemental bases too but why do I keep ...
- 3,050
9
votes
1
answer
2k
views
Hydrolysis of salts containing amphiprotic anion
I am trying to understand the derivation of pH of salt containing amphiprotic anions, but I am facing some difficulty:
Ionisation:
$\ce{HCO3^- + H2O <=> CO3^2- + H3O+};\quad K_\mathrm{a_2}...
- 836
8
votes
2
answers
1k
views
Why proton concentration is divided by 10⁻⁷?
I am reviewing the book Biochemistry Concepts and Connections by Appling, Cahill, and Mathews and I cannot understand why they divide by the hydrogen concentration by $10^{-7}$. Why not just leave it ...
- 191
8
votes
2
answers
3k
views
Should the 'a' in the acid dissociation constant (Ka or pKa) be capitalised?
In science, the negative logarithm of the acid dissociation constant is denoted $\mathrm{p}K_\mathrm{a}$ or $\mathrm{p}K_\mathrm{A}$ depending on the source (lowercase "a" or uppercase "A"). Since it ...
- 183
8
votes
2
answers
15k
views
Calculating pH of diprotic and amphoteric solutions
I am trying to understand this problem and its corresponding solution (complete solution not shown)
First off, from the above one can see that the equilibrium constants when $\ce{H2ASO4-}$ donates ...
- 3,256
7
votes
2
answers
2k
views
Which salt will best be able to buffer the addition of HCl?
From these three salts, which will be best able to buffer the addition of $\ce{HCl}$?
ammonium chloride
sodium carbonate
ammonium acetate.
I think sodium carbonate is the right choice because when ...
- 81
7
votes
2
answers
7k
views
Combining acid dissociation constants to determine pH of diprotic acid
If I have a diprotic acid with $K_{\mathrm{a1}}$ and $K_{\mathrm{a2}}$ as the acid dissociation constants, why can't I calculate the final $\mathrm{pH}$ using $K = K_{\mathrm{a1}}\cdot K_{\mathrm{a2}}$...
- 235