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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.

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6k views

I need to find the Ka of a weak acid in titration with a strong base

I have been working on this lab forever and have not been able to get a $K_\text{a}$ anywhere close to the accepted value. I’m sure I’m missing something really simple. We titrated $\ce{CH3COOH}$ ...
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1answer
1k views

Weak base titrated with a strong acid

If you have a weak base XOH titrated with a strong monotonic acid, where do you start with that? Would you first have the base react with water and break up and determine how much of it does? Or just ...
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1answer
9k views

Principle of potentiometric titration

In potentiometric titration between ascorbic acid and iodine, when we plot the graph of EMF with volume of iodine consumed, we get a sudden decrease in EMF at equivalance point--why? It is also ...
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1answer
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Explaining the colour change in the potassium permanganate titration of iron(II) ions

In the redox titration: $$\ce{MnO4- + 8 H+ + 5 Fe^2+ -> Mn^2+ + 4 H2O + 5 Fe^3+}$$ the colour change which occurs is purple to colourless, because of the decreased concentration of permanganate ...
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Why Mohr's salt and not FeSO4 in titration? [closed]

During titration of $\ce{KMnO4}$, we use Mohr's salt instead of ferrous sulphate salt to prepare the standard salt solution. Is it done to prevent oxidation of $\ce{Fe^2+}$ to $\ce{Fe^3+}$ before the ...
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42 views

Neutralization reaction with insoluble salt (weak acid, strong base)? [duplicate]

Consider the following reaction. $\ce{2 HF(aq) + Ca(OH)2(aq) -> CaF2(s) + 2 H2O(l)}$ The reaction produced a fairly insoluble salt. Assume that this reaction proceeds entirely to completion as ...
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265 views

Titration: Standardizing NaOH using PHI

Q: A student standardizes sodium hydroxide by weighing out 1.207 grams of potassium hydrogen iodate, dissolving the compound in water and titrating to a suitable endpoint: If the volume to reach the ...
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1answer
132 views

Percent Dissociated from Titration Curve

Question 818 references the titration curve. Answer is A because $\ce{H+}$ conc $= 10^{-4}$. This is conc of dissociated acid. The conc of the undissociated acid is the original concentration minus ...
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2answers
6k views

How to determine the equivalent weight of CO2

We were estimating dissolved $\ce{CO2}$ in water by American Public Health Association method. It was a titrimetric method using phenolpthalein indicator. Titrant used was $\ce{NaOH}$ and analyte was ...
2
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1answer
364 views

Does titration usually always involve neutralization?

I've been doing titration exercises that involve figuring out the molarity of an unknown solution when you know the molarity of another (so like knowing the molarity of solution A but figuring out the ...
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1answer
900 views

What is the meaning of delta squared?

I know that $\Delta x = x_2 - x_1$. This is well known Therefore, it follows that $\frac{\Delta a}{\Delta b}$ = $\frac{a_2 - a_1}{b_2 - b_1}$ (Unless I missed an elementary math class!) Now, I found ...
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1answer
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How to quantify caffeine content in coffee?

How do I titrate caffeine from coffee to estimate the percentage of caffeine in coffee? I have tried using iodine solution, sulfuric acid, and sodium thiosulfate to no avail.
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4answers
118k views

How come water would not affect the results of a titration?

We were told to rinse the buret with the base so that the concentration won't be messed up, but when it comes to the flask that is going to hold the acid, there is no need to rinse, because it would ...
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2answers
419 views

Regarding Kw, titrations, and pH

So I have need of performing a titration upon a fruit juice to determine acid concentration. I will be using 1M NaOH as my base. Seeing as the solution will be coloured, it would be difficult to use ...
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1answer
902 views

Why do some salt ions in solution conduct electricity better than others?

My experiment involves a potentiometric titration, and I have used $\ce{AgNO3}$ as a titrant and KCl/KI/deionised water only as an analyte. In the image below of my data, the potential difference as ...
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1answer
43 views

Evaluate indicator choice (phenolphthalein)

A student wishes to find the concentration of a $\pu{50 mL}$ solution of acetic acid $(K_\mathrm{a} = \pu{1.8e-5}).$ He performs a titration using a solution of $\pu{0.2 M}$ sodium hydroxide. The ...
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1answer
45 views

Neutralisation Reaction Confusion

What will happen when $\pu{1 mol}$ of $\ce{H2SO4}$ reacts with $\pu{1 mol}$ of $\ce{NaOH}$? Will $\pu{1 mol}$ each of $\ce{NaHSO4}$ and water be formed? Or will $\pu{0.5 mol}$ of $\ce{H2SO4}$ will ...
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1answer
157 views

Regarding Analysis for CO2 Absorption in NaOH

Background Lab experiment, packed glass column (random packing of metal/ceramic material), countercurrent gas absorption, flowrates measured using rotameters, $rt \approx 27^\circ C$. 2 N NaOH flows ...
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2answers
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Propagation of Uncertainties

I have five values for the volume of sodium hydroxide needed to neutralise a fixed quantity of hydrochloric acid, each trial with an uncertainty of 0.05 mL. If I take the average of these five values, ...
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1answer
4k views

Titration curve of a diprotic acid with a strong base titrant

I have wonders regarding the titration curve of the titration of sulphuric acid, or any diprotic acid, with a strong base. I am aware of the fact that a diprotic acid is protolysed in two steps but, ...
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2answers
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Phosphoric Acid Titration

I physics graduate student, but I teach an interdisciplinary lab for the university which incorporates biology, physics, and chemistry. We recently added a weak-acid titration lab to the course and ...
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1answer
3k views

Is there a certain amount of titrant that is ideal?

For an AP chem lab dealing with determining the amount of citric acid in orange juice by titrating with NaOH, one of the discussion questions goes like this: Choose an amount of beverage to be ...
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3answers
35k views

Why does pKa of a acid-base indicator equal to the pH when the equivalence point is reached?

To be honest, I just don't get it. I had this question while reading a Chemguide article, on this topic: I think my confusion is caused by the way I look at pKa of acid-base indicator. Should you ...
2
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1answer
795 views

Potentiometric titration using a pH meter

Why is the pH of a buffer solution measured before measuring the pH of an unknown solution? I do not have any idea about it. I had read a chapter about ionic equilibrium and electrochemistry, but have ...
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2answers
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What's happening at the beginning of a weak acid titration?

At the beginning of a Weak Acid/Strong Base titration curve there is a sharp decrease in $[\ce{H+}]$ and a sharp increase in pH before the ratio between the weak acid and it's conjugate base becomes ...
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1answer
105 views

Application of Nernst Equation in Potentiometric titration of Fe2+ with Ce4+

It is well Known that to find $E_{cell}$ during titration of $Fe^{2+}$ with $Ce^{4+}$ we consider 3 domains: Before Equivalance point , $E_+ = E_{Fe^{3+}/Fe^{2+}}^o+\frac{RT}{nF}log\frac{[Fe^{3+}]}{...
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2answers
663 views

What does the small, steep curve at the very beginning of a weak acid strong base titration curve come from?

I understand that a buffer solution is being made, but I don't understand why the titration curve is different from a strong acid strong base one (apart from the steeper pH change). I understand the ...
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1answer
126 views

Is it possible to calculated the concentration of hydroxide ions from the known concentration of hydronium ions?

I came across the following question in Chapter 15 (Acids and Bases) of Holt High School Chemistry: Neutralizing $\pu{5.00 L}$ of an acid rain sample required $\pu{11.3 mL}$ of $\pu{0.0102 M}\ \ce{...
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1answer
565 views

Estimation of CO2 by titrimetric method using phenolphthalein indicator

We were estimating dissolved $\ce{CO2}$ in water by American Public Health Association (APHA) method. It was a titrimetric method using phenolphthalein indicator. Titrant used was $\ce{NaOH}$ and ...
2
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1answer
453 views

What are the reactions occurring during the titration of a carbon dioxide contaminated water sample with diluted sodium hydroxide solution?

During estimation of dissolved $\ce{CO2}$ in water, we took a water sample, added few drops of phenolphthalein and titrated it against dil $\ce{NaOH}$. Questions What are the reactions that happen: ...
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1answer
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How to calculate the concentration of a monoprotic organic acid that was extracted into an ethyl ether layer?

Compound A is a monoprotic organic acid. If $25.0~\mathrm{mL}$ of a $0.456~M$ solution of A in water was extracted with $25.0~\mathrm{mL}$ of ethyl ether and it was determined experimentally that $5....
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1answer
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Stoichiometry and iodometric titrations

$1.25~\mathrm g$ of a sample of bleaching powder is dissolved in $100\ \mathrm{mL}$ of water. $25\ \mathrm{mL}$ of it are treated with $\ce{KI}$ solution. The iodine so liberated required $12.5~ \...
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1answer
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Why is copper(II) carbonate not selected as an unknown compound for back titration? (Whereas another unknown carbonate is used instead?)

Why is copper(II) carbonate not selected as an unknown compound for back titration? (Whereas another carbonate is used instead) I know that the carbonate to be provided on the day (not Copper (II) ...
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1answer
17k views

Calculating pH: Weak Acid, Strong Base

This is a question that had me puzzled for quite a while. I feel that information is missing. A weak acid, $\ce{HA}$, $K_a = 1.0$ x $10^{-4}$, is titrated with $\ce{NaOH}$. At the equivalence point,...
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1answer
6k views

Solubility of calcium hydroxide determined by titration

For a lab I had to determine the solubility and $K_{sp}$ of $\ce{Ca(OH)2}$ by performing two different titrations. I am given the formula to find solubility in molarity it is as written below. ...
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1answer
227 views

Ratio of conjugate bases of a tricarboxylic acid

Hi does anyone know how to solve this question? A tricarboxylic acid $\ce{H3A}$ has three different types of $\text{p}K_\text{a}$ $(\text{p}K_\text{a, 1} =2.0,$ $\text{p}K_\text{a, 2}=5.0,$ $\text{...
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1answer
56 views

pH throughout a titration

Estimate the $\ce{pH}$ of the solution that results when $\ce{75.0 mL}$ of $\ce{0.275 M HCl}$ is added to $\ce{50.0 mL}$ of $\ce{0.275 M Na2HPO4 (aq)}$. My book gives the successive $\ce{Ka}$ values ...
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1answer
407 views

How to find the vitamin C content of orange juice?

I'm an IB chemistry SL student doing an IA on the vitamin C concentration of orange juice. We haven't learned about the titration process, so here is what I have done so far: $\ce{5KI + KIO3 + 3H2SO4 ...
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1answer
880 views

Can titrant and analyte be swapped?

I just did a titration experiment at school, our teacher told us multiple times to add the solution of known concentration into the solution of unknown concentration. I am wondering if we can do it ...
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1answer
759 views

Potassium permanganate to analyze iron compounds [closed]

In my lab, I used potassium permanganate in order to analyze the amount of iron in a compound with iron in the +2 oxidation state using titration. My question is how would this analysis be different ...
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1answer
6k views

How to find the concentration of an of ammonia solution by titration with nitric acid?

I am stuck with this question I am doing: To determine the ammonia ($\ce{NH3}$) concentration in a cleaning product, a chemist diluted 20 mL of the product to 500 mL. Of the 500 mL solution, 25 mL ...
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1answer
1k views

Is this asking for the equivalence point?

Is this question asking for the equivalence point of the titration curve? At what point does the concentration of acetic acid equal the concentration of the acetate ion? What is the pH of the ...
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1answer
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Titration of NaOH with acetic acid

During a titration lab where 0.1 N of NaOH is added to 20 mL of acetic acid with the same concentration, the equivalence point occurred after adding about 70ish milliliters of NaOH (different peers ...
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1answer
852 views

Calculation of volume required for titration with dibasic acid

Here is a problem: Titrate $1 M$ sulfuric acid with $\pu{50 ml}$ of $1 M$ sodium hydroxide solution. What volume of sulfuric acid will be required for neutralization. This is a simple problem. My ...
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1answer
210 views

Why wash a sample before titration?

In the awwa notebook for $\ce{Na2SiF6}$ determination, why it is required to wash the product sample in an alcoholised $\ce{KCl}$ solution before titration?
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1answer
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Titrating and the addition of acidic distilled water

I have read numerous online questions similar to the one I am about to ask. But for most of them the answer has been that the reason one can add water to the unknown concentration solution during a ...
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1answer
162 views

pKa vs range in choice of an indicator

When choosing the ideal indicator during a titration, there are two considerations to keep in mind: The pH = pKa of the equivalence point The indicator has a small range (<±1) over which it can ...
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0answers
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Why is the titratable acidity of my wine going down as it ages and oxidises?

I am currently studying chemistry in grade 12 studies and I have come across a halt in my investigation. The experiment was to see how the increase in ethanol would lead to a more acidic wine, ...
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0answers
433 views

Titration homework question

My friend sent me this for his homework, and I haven't done a titration calculation in years. A student titrated $\pu{10.00 mL}$ aliquots of her unknown amino acid solution with standard $\pu{0....
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0answers
37 views

Concentration of acid when titration has reached equivalence point? [duplicate]

I'm currently working with a lab report concerning titration. One of the tasks is to calculate the concentration of the weak acid ($\ce{HOAc}$) and the strong acid ($\ce{HCl}$) at the equivalence ...