All Questions
12
questions
1
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0
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410
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Determine the pKa of a diprotic acid by titration (if pKa1 is similar to pKa2)
Determining the acidity constants of a diprotic acid (in my case, tartaric acid) by titration with NaOH and pH-meter is not possible if pKa2 - pKa1 < 2.
This is because there are no "pH jumps&...
- 109
1
vote
0
answers
485
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Equivalence point pH derivation of a tribasic acid
Considering $\pu{100 mL} \ \pu{0.1 M} \ \ce{H3A}$ and $\pu{0.1 M} \ \ce{NaOH}$ titration curve:
I understood the half equivalence points, but couldn't understand the reason why $\mathrm{pH} = \frac{1}...
- 412
0
votes
2
answers
787
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Calculating the pH of a 'buffer' solution?
Question: Determine the $\mathrm{pH}$ of the solution resulting when $\pu{100 cm^3}$ of $\pu{0.50 mol dm-3}$ $\ce{CH2ClCOOH}$ is mixed with $\pu{200 cm^3}$ of $\pu{0.10 mol dm-3}$ $\ce{NaOH}$.
The ...
- 153
-3
votes
1
answer
5k
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pKa = pH for strong acid — strong base?
I have learnt that for a weak acid — strong base titration, $\mathrm{p}K_\mathrm{a} = \mathrm{pH}$ at the half equivalence point.
However, the same conclusion is not drawn when discussing strong acid —...
- 153
4
votes
3
answers
253
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Is pK_{In} = pH at equivalence point still true for weak basic organic indicators?
I am reading Ostwald Theory of Titration which says that indicators are organic weak acids or bases.
To prove the relation that $\mathrm{p}K_\mathrm{In} = \mathrm{pH}$, the textbook uses the following ...
- 261
1
vote
1
answer
179
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Calculating pH of weak base and strong acid: Why is K(a) not required?
Question: 35mL of 1.5M $\ce{HCN}$, a weak acid(K(a)= $6.2*10^{-10}$) is mixed with 25mL of 2.5M $\ce{KOH}$. Calculate the pH of final solution.
The solution given in my textbook is as follows:-
$\ce{...
user62318
0
votes
1
answer
3k
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pKa value of an indicator
Can we deduce the actual value of $\mathrm{p}K_\mathrm{a}$ of an indicator if the $\mathrm{pH}$ range has been given?
I know that $\mathrm{pH}$ range is physically the range of values over which an ...
- 54
1
vote
1
answer
488
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Why doesn't pH = pKa1 in the buffer zone for this titration?
Below is an image from my textbook representing the titration curve for the titration of $5.00\ \mathrm{mL}$ of $0.010\ \mathrm M$ $\ce{H2S2O3}$ with $0.010\ \mathrm M$ $\ce{KOH}$, which has $\mathrm ...
- 2,109
0
votes
1
answer
12k
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Find the half equivalence point
How to find the half equivalence point knowing the pH, molarity, titrant added at equivalence point?
This a fairly straightforward and simple question, however I have found many different answers to ...
3
votes
3
answers
6k
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Phenolphthalein as a indicator for the titration of benzoic acid
Question: Justify the use of phenolphthalein $(\mathrm{p}K_\ce{in}=9.4)$ as a indicator for the titration of benzoic
acid $(K_\mathrm{a}=6.3\times 10^{-5})$ with $\ce{NaOH}$.
My attempt:
I can ...
- 151
0
votes
1
answer
6k
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Determining the nature of common pH indicators (methyl orange) using Le Chatlier's principle
I got some good information about this topic yesterday, and I understood what I was told, but I have come up with a specific way of phrasing the problem I'm having. It is slightly different than ...
- 149
2
votes
2
answers
37k
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Titration of H3PO4 with NaOH
I came across an ionic equilibrium problem stating:
Find the pH when 150 ml 1 M $\ce{NaOH}$ has been added to 100 ml 1 M $\ce{H3PO4}$.
I'm stuck with this question. What I know:
$$\ce{H3PO4 + NaOH ...
user14857