Questions tagged [titration]
A laboratory method to determine the concentration of an analyte in solution. The solution volume plays a key role in the analysis.
472
questions
-3
votes
2answers
41 views
2 Weak Acids + Strong Base Titration [closed]
100ml of a solution which is 0.05M in the acid HA(pKa=4) and 0.10M in HB{pKa=8} is titrated with 0.2M NaOH. Calculate the pH at the first equivalence point
The answer is given out to be 5.85 but not ...
0
votes
0answers
31 views
Acidity and structure of EDTA at different pH
I was conducting complexometric titrations to measure the concentration of magnesium ions in my solution.
But of course, as EDTA is a chelating agent, knowing it’s structure and ionization form at ...
0
votes
0answers
38 views
Does Sodium Precipitate with anything to find the level when titrating?
I am trying to find sodium in animal feeds. I already have a procedure to find chloride by using Mercuric Nitrate to form Mercuric Chloride using a titration method but am having a difficult time ...
1
vote
1answer
39 views
Understanding weak acid-strong base titration
Today I stumbled across a website which defined the titration of weak acid and strong base as the following:
"The titration of a weak acid with a strong base involves the direct transfer of ...
2
votes
1answer
72 views
Titration of CH3COONa with HCl and pKa determination from half equivalence point
I am trying to experimentally determine the $\mathrm{p}K_\mathrm{a}$ of acetic acid by titrating sodium acetate with $\ce{HCl}$. The $\mathrm{pH}$ curve starts in the alkaline region (since sodium ...
0
votes
1answer
27 views
Approximation for pH calculation with diluted acids in weak-strong titration curve
I was wondering how one could calculate small pH changes in titrations with dilute acids.
As we know, usually we approximate the pH by saying that the conversion is quantitative. For example, when we ...
1
vote
0answers
36 views
Function describing pH vs. volume of base used in titration [duplicate]
Sketch a graph of $\mathrm{pH}$ vs. volume when $\pu{50.0 cm^3}$ of $\pu{1 M}$ $\ce{HCl}$ is titrated with $\pu{1 M}$ $x\,\pu{cm^3}$ $(x \in (0,50))$ of $\ce{NH3}.$
As $\ce{HCl}$ fully dissociates, I ...
0
votes
0answers
28 views
Novalucol back titration lab calculations
I had a lab today where we had the goal of figuring out how many moles of HCl were neutralized by one tablet of Novalucol. Novalucol is an antacid tablet containing magnesium hydroxide and calcium ...
2
votes
1answer
106 views
How to derive formulas for n factor of different types of reactions?
While studying Redox reaction, I came across this term called n-factor which seems to me as a short-cut trick to do the questions quickly. Since I am preparing for a competitive exam so our chemistry ...
-1
votes
1answer
45 views
Prepairing a Sodium Acetate buffer - Meaning of molarity
We have instructions to prepare a "50 mM Sodium Acetate, pH 5 solution". I am not entirely sure what does the molarity refer to in this case. Does it mean:
Add Sodium Acetate salt up to 50 ...
1
vote
1answer
59 views
NaOH + atmospheric CO2: Unexpected results troubleshooting
I've conducted an experiment where a solution of $\pu{4.2 M}$ $\ce{NaOH}$ was left exposed to atmospheric $\ce{CO2}$ for a period of time and titrated using potentiometric titration and potassium ...
0
votes
1answer
47 views
Using samples in titrations
I've never done an experiment before. So, the methodology provided in this pdf is quite confusing.
Link to the pdf: https://www.canterbury.ac.nz/media/documents/science-outreach/vitaminc_iodine.pdf
So,...
1
vote
0answers
47 views
Understanding equivalence point [closed]
I read this passage:
“It is important to emphasize that, while a strong acid/strong base titration will have its equivalence point had a pH of seven, the equivalence point does not always occur at pH ...
3
votes
0answers
45 views
How measured content of Calcium Carbonate in eggshells change with the use of different acids?
I am investigating the calcium content of chicken eggshells. The only literature I can find on this consistently and solely depend on the use of HCl to conduct back titration. I conducted the ...
0
votes
2answers
97 views
Could the pH in the equivalence point of strong acid and strong base titration be greater than 7? [duplicate]
I have HCl and NaOH titration and in the equivalence point I get pH=8.6, but the pH must be 7 in this kind of titration, then why this happen? Does it possible that I don't take enough points in the ...
3
votes
1answer
156 views
How to determine the equivalents of OH- in a titration curve
How does one go about determining the equivalents of $\ce{OH-}$ needed for the titration of a weak acid. For example here is the titration curve for Aspartate:
Why is the equivalents for $\mathrm{p}...
0
votes
0answers
58 views
Which method has the highest yield of calcium sulfate?
I'm not sure which of following two methods will give better yields for $\ce{CaSO4}$:
A. Add dilute $\ce{HNO3}$ to $\ce{CaCO3}$, followed by dilute $\ce{H2SO4}$; or
B. Titrate aqeuous calcium ...
1
vote
0answers
34 views
Titration of H+ by iodometry
Propose a titration protocol for a hydrochloric acid solution of approximate concentration 0.1M using the solutions and materials available.
Solutions:
-$V_0$ = 20mL of hydrochloric acid solution of ...
3
votes
1answer
82 views
Acid titration of sodium acetate in the presence of sodium ethoxide, is it possible?
I have an aqueous solution of ethanol of $30 - 40\text{ V%}$ that contains a few (unknown) $\text{%}$ ethyl acetate (ethyl ethanoate - $\ce{EtOAc}$).
I wonder if I can quantitatively determine the $\...
-2
votes
1answer
40 views
Concentration of weak acid neutralized by strong base [closed]
I've got a question that should be simple enough but I must be doing something very wrong.
A $\pu{10mL}$ sample of $\ce{H2SO3}$ is neutralized by $\pu{18.6mL}$ of a $\pu{0.10M}$ strong base. Find the ...
3
votes
1answer
188 views
Procedure for measuring EC
Most of the procedures on the internet are of a university research lab level. Is there a simpler method I could use to determine the concentration of EGCG
3
votes
0answers
33 views
My EDTA titration isn't giving the right titre
I am, as a fun off-syllabus investigation, looking at hard water and how effective the EDTA titration method is, for permanent and temporary hard water.
I ran a titration today and had horrific ...
2
votes
0answers
29 views
Titration of weak acid and strong base at low concentrations [duplicate]
Titration continues until one of the reactants (the one in conical flask) turns out to be a limiting agent as far as I know. From the titration of a weak acid and a strong base, I could learn that the ...
0
votes
0answers
35 views
Preparation of phosphate buffer of ph 7.4
Can I make a phosphate buffer of pH 7.4 starting with phosphoric acid and then adding NaOH until the pH reaches 7.4. What are the disadvantages of using this method over sodium phosphates?
0
votes
0answers
32 views
Temperature at which the reaction Oxalic acid + KMnO4 becomes autocatalytic
As described many times, the reaction between oxalic acid and potassium permanganate can be autocatalytic due to the production of Manganese ions.
I've read that this only occurs at higher ...
-1
votes
1answer
32 views
titrating a weak acid with strong base in the present of buffer
I would like to get a neutral salt solution for a weak acid whose pKa is 3.42. This weak acid is in the form of solution (now is 20% w/w), thus I cannot directly dissolve the powder into the buffer ...
2
votes
0answers
160 views
Will potassium permanganate react with ferric chloride?
I came across a question :
Which of the following compound does not decolourise an acidified solution of $\ce{KMnO4}$?
Answer was:
After doing a bit of research I found that $\ce{KMnO4}$ oxidises $\...
0
votes
0answers
34 views
Why can indicator pKa be less than the pH at equivalence?
An indicator usually has a pH at equivalence tolerance range around its pKa value that is suitable for titration. However, if the pH at equivalence exceeds the indicator's pKa, wouldn't most of the ...
1
vote
0answers
52 views
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}...
0
votes
2answers
106 views
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 ...
9
votes
2answers
389 views
How to (numerically) model a phosphoric acid titration curve
I've been learning how to simulate a 1M phosphoric acid titration curve using numerical methods in R.
So far has this has been the best curve:
Notice how it flattens out (artificially) towards the ...
-3
votes
1answer
116 views
Determining iron content by titration
The redox reaction is
$$\ce{KMnO4-(aq) + 8 H+(aq) + 5 e- -> Mn^2+(aq) + 4 H2O(l)}.$$
Where does $\ce{H+}$ come from in this reaction? What happened to $\ce{K+}$ in potassium permanganate?
2
votes
1answer
149 views
Titration curve equation/function
How can I create a graph of a titration curve (acid-base, strong or weak, not something specific), with an equation or a function. In other words, what is the equation that describes such a curve that ...
3
votes
1answer
75 views
EDTA titrations of singly charged cations
It is well known that EDTA can be used for titrations involving complexations of highly charged metal cations, with the most well known being those of the alkali earth metals and transition metals. ...
1
vote
1answer
126 views
How is the selective complexometric titration testing equation simplified?
When there is $\ce{N^m+}$ and $\ce{M^n+}$ metal ions in a solution with respective m and n charge,
$\ce{N^{m+}, M^{n+}}$ reacts with EDTA($\ce{Y}$) as follows:
$$\ce{N^m+ + Y^4- <=> NY^{m-4}}$$...
0
votes
2answers
64 views
Writing a chemical equation with a reactant of unspecified chain length [closed]
Would appreciate it if I got some general tips and hints and not the solution cause I'm trying to learn from this question :)
The question is as follows:
FA1 is a solution containing $\pu{5.00 g dm-3}...
-2
votes
1answer
102 views
what is the concentration of EDTA after titration with Zinc Metal?
I take $\pu{1g}$ of zinc metal and after dissolving, diluting it to $\pu{500 ml}$ and adjust the $\mathrm{pH}$ of $\pu{50 ml}$ of it to make titration with an unknown concentration of EDTA.
I found $\...
-1
votes
1answer
61 views
Can I measure the molarity of Acetic Acid titrating Vineger with Sodium Hydroxide?
Imagine I have 5 g of vineger which I titrated with 33 mL of 0.1M Sodium Hydroxide (NaOH).
I tried V₁S₁=V₂S₂ formula but It needs the volume of the acid.
I have tried to calculate the volume with W=...
0
votes
1answer
256 views
Combining solutions with multiple concentrations - Mixing NPK fertilizer ratios
I'm trying to mix my own fertilizer to grow some peppers.
Fertilizers are labeled with NPK ratios, so mixing two volumes and finding the result is easy: Just multiply the concentration of each ...
0
votes
2answers
78 views
Is this stoichiometric question answerable? (unknown variable)
This question kind of borders on the fields of both semantics and math, as well as chemistry, but I still believe this is the right place to ask.
On a test I took, a question was posed as such:
Via ...
2
votes
0answers
49 views
Sodium Deoxycholate titration assay
Purchasing chemicals online often I see "Sodium Deoxycholate, ≥97% (titration)" offers. Is there any publicly available titration protocol I can use to confirm that statement in my very ...
1
vote
1answer
489 views
What concentration is phenolphthalein indicator ? 1% or 0.1%
I read some information about phenolphthalein indicator, some websites suggested phenolphthalein indicator of 1%, others mentioned phenolphthalein indicator of 0.1%. What is the difference of both of ...
1
vote
2answers
696 views
Understanding strong acid titrated with weak base graph
I don’t understand why the conductivity doesn’t change after the equivalence point. To my understanding, at the equivalence point there is $\ce{NH3}$, $\ce{NH4+}$ and $\ce{Cl-}$ in the solution. As ...
-3
votes
1answer
1k views
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 —...
2
votes
2answers
110 views
Why is the gradient of the curve of a strong base titrated with strong acid small up until equivalence?
I understand the cause of the sharp decrease in pH upon reaching the equivalence point, but I don't understand why addition of relatively large amounts of the strong acid would be accompanied with ...
1
vote
0answers
41 views
Best pH indicator for titration
Which substance is best suited as a pH indicator for titration of $\pu{15 mL}$ of $\pu{0.1 M}$ ascorbic acid $(K_\mathrm{a} = \pu{7.9E-5})$ with $\pu{1.0 M}$ sodium hydroxide solution?
Using the image ...
2
votes
1answer
156 views
Equivalence point of titration of Sodium carbonate
The pH at the equivalence point of titration of $\ce{Na2CO3}$ solution with $\ce{HCl}$ is around 3.7, as shown in this titration curve:
At this point, the following reaction is completed:
$$\ce{...
-1
votes
1answer
572 views
Will washing a conical flask with deionised water to remove splashes affect the titration result?
When performing a titration, once the acid/base in the burette is slowly released into the conical flask, it may splash onto the sides of the conical flask. It is then advised that we wash the sides ...
0
votes
1answer
55 views
When titrating to find the concentration of a dissolved acid, does the volume of solvent matter?
I am conducting a titration to find the mass of aspirin present in tablets. I will be dissolving the aspirin tablet into a solution of ethanol and distilled water to dissolve it. But, does the volume ...
1
vote
1answer
37 views
How can I mask the Chromium (III) and Chromium (VI) ions in my solution?
I want to conduct a quantitative analysis on my acid etching solution for my Aluminum pre-treatment process. The easiest way for me to conduct my quantitative analysis of Al is through complexometric ...
