All Questions
Tagged with equilibrium acid-base
357
questions
5
votes
2
answers
3k
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Calculating approximate pH of polyprotic acids
When I took up ionic equilibria and titrations after a long break, I found it hard to solve the questions regarding pH calculations of polyprotic acds. Consider these two questions as examples:-
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21
votes
3
answers
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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
8
votes
2
answers
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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
3
votes
2
answers
4k
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Strong acid equilibrium
So a teacher at school told me that strong acids do not create an equilibrium in general, while weak acids do (thats the difference, strong acids namely ionize completely). However, I lately stumbled ...
- 335
0
votes
1
answer
3k
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How to estimate pH?
How you you calculate/estimate the pH of a solution with 3 components all of different pHs?
Is there a paper describing this?
For example:
0.1M Buffer PCTP at pH 9.5
1.6M Sodium Dihydrogen Phosphate ...
- 395
125
votes
7
answers
87k
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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
-1
votes
3
answers
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Which one is nitric Acid, HNO3 by itself, or when it is included in H2O?
This is a quote from my Chemistry textbook:
Nitric acid ionises according to the following equation:
$$\ce{HNO3(l) + H2O(l) -> H3O+(aq) + NO3- (aq)}$$
I know that the formula for nitric acid ...
- 289
13
votes
3
answers
9k
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How can the equilibrium shift, while Kc remains constant?
Consider the following reversible reaction.
$$\ce{Cr2O7^2-(aq) + H2O(l) <=> 2 CrO4^2-(aq) + 2 H+(aq)}$$
What will happen to the position of equilibrium and the value of $K_c$ when more $\ce{H+}$ ...
- 557
2
votes
2
answers
631
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How many of different types of chemical species are in a certain volume of aqueous solution of an acid
The acid in question has $\mathrm{p}K_\mathrm{a}$ about 1.29. Density of 98% w/w solution is $d=\pu{1.323 g/cm^3}$. I would like to find the number of undissociated acid molecules ($\ce{HX}$), water ...
- 41
12
votes
3
answers
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How do I calculate the degree of dissociation in equilibrium?
In my textbook, for calculating the percentage dissociation of $\ce{HF}$ for the given equation:
$$\ce{HF + H2O <=> H3O+ + F-}$$
The solution is:
Initial Concentrations
$$[\ce{HF}] = 0.08~\...
- 261
4
votes
2
answers
3k
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Why is water ignored in the ionic equilibrium of HF?
While trying to understand the solution of a problem given in my textbook, I realized I'm having some difficulty with the solution. The problem is as follows:
The ionization constant of $\ce{HF}$ ...
- 261
26
votes
4
answers
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What software can calculate aqueous solution equilibria?
What software is available out there to calculate the equilibrium in a set of reactions in aqueous solution? In particular, I'm interested in software general enough to simulate things like titration ...
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