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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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1answer
45 views

Phenolphthalein and methyl orange end points comparison [on hold]

In determining the solubility constant for Ca(OH)2, how does phenolphthalein end point compare with the methyl orange end points?
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40 views

How do indicators work in a titration? [on hold]

How do they change color in a titration?
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74 views

How can you use indicator titration to determine the pH of a complex solution like ocean water if at all

Could you measure the pH of ocean water by using a strong acid-weak base titration? I was thinking that you could set up a standard titration with ocean water as the "unknown", and drip the known HCl ...
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1answer
45 views

Acid-base titration: Unknown base in burette or flask?

While finding the concentration of $\ce{NaOH}$ via titration with $\pu{0.05M}$ Oxalic acid solution (in our lab) we put NaOH in the burette whereas added phenolphthalein to oxalic acid in titration ...
1
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1answer
49 views

When disolving a iron pill for titration, why do I use sulfuric acid instead of nitric or hydrochloric acid?

In a titration to decide the iron content of a pill we dissolved the iron in sulfuric acid and then titrated it with cerium(IV) sulfate. But I just wondered what's wrong with using nitric and ...
1
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1answer
48 views

Winkler's method in the absence of iodide

I'm currently doing an IB chemistry individual investigation on the effect of adding bleach to water on the water's dissolved oxygen content. I've used Winkler's method for this and I'm just wondering ...
6
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1answer
8k views

Why, in titration, is universal indicator not commonly used?

My teacher said that we always used indicators such as methyl red, methyl orange, litmus, phenolphthalein, etc. rather than universal indicator. I don't understand why, though, would not universal ...
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3answers
40k views

Volume required to dilute solution for a pH change

A $\pu{100 mL}$ solution of $\ce{NaOH}$ has a $\mathrm{pH}$ of $13$. What volume of water in $\pu{mL}$ must be added to change the $\mathrm{pH}$ to $11$? My steps: Begin by calculating conc. of $[\...
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0answers
18 views

Factors affecting hardness of water - EDTA titration

I am thinking of doing a project involving EDTA complexometric titration to determine the hardness of the water. I am not sure if the pH will affect the hardness of the water. If it did, I would ...
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2answers
59 views

Finding molarity of hyposulfite solution used in titration

$\pu{0.1 g}$ of $\ce{KIO3}$ is treated with excess $\ce{KI}$ solution. The liberated iodine required $\pu{44 ml}$ of $x$ molar hypo solution. Calculate the value of $x$. I have used the equivalent ...
-1
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1answer
103 views

Titration/ Separating Soluble Salts/ NaHSO4

When performing titration between NaOH and H2SO4, both Na2SO4 and NaHSO4 are formed (both are soluble in water), is there any method to obtain crystals of NaHSO4? (Maybe by separating two soluble ...
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32 views

Calculating the solubility of aspirin in water

I am trying to investigate the relationship between the solubility of aspirin in water with the relationship to some variables. In my investigation, I seem to be stuck with the calculation of finding ...
1
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1answer
53 views

Why do strong polyprotic acids not dissociate completely, whereas strong bases with multiple (OH)- groups do?

$\ce{H2SO4}$ is a strong acid, which follows the reaction $$\ce{H2SO4 -> HSO4- + H+}$$ Not $$\ce{H2SO4 -> SO4^2- + 2 H+}$$ However, $$\ce{Ba(OH)2 -> Ba^2+ + 2OH-}$$ Is there a reason why ...
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1answer
63 views

pH After Titration

50mL $\ce{SO2}$ titrated with 0.1M of $\ce{KBrO4}$ with reaction: $$\ce{KBrO4 + 4SO2 + H2O -> 4H2SO4 + KBr}$$ The equivalent point is reached when the volume of $\ce{KBrO4}$ is used as much 50mL. ...
-1
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1answer
56 views

Redox Titration in investigating change of Iron in Avocado [closed]

I'm trying to investigate the change in iron in an avocado as it ripens. I'm planning on using redox titration but still a bit unsure of how to carry out the investigation (method). Do you have any ...
2
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1answer
125 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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1answer
5k views

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 ...
6
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1answer
4k views

Buffer formation in weak acid/strong base titration?

I'm a little confused about what happens when you titrate a weak acid or base. For example, let's say that you are trying to titrate a weak acid. Based on this question, it seems like the weak acid ...
4
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2answers
183 views

Is there a potentiometric method for monitoring salt formation in organic solvent?

I work in a pharmaceutical R+D lab, and currently aim to develop a validatable potentiometric method for determining the optimal amount of acid to add to a basified small organic molecule for ...
1
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1answer
145 views

Why is a titration necessary? Why can't we just compare the moles of the acid and base?

For the following question: $\mathrm{1g}$ of $\ce{Mg(OH)2}$ is completely dissolved in $\mathrm{25}$ mL of $\mathrm{0.5}$ M $\ce{HCl}$. This solution is then titrated with $\mathrm{0.1}$ M $\ce{NaOH}...
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1answer
78 views

Replacement for Centrifuge in Calcium Content Determination

Basically, I'm performing a lab investigation to determine calcium content in different milk sorts. Since my school didn't have any EDTA, I'm using Sodium Oxalate to form a precipitate with Calcium ...
7
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1answer
250 views

How to derive the conductivity titration curve which accounts for salt formation

I derived an equation that gave me the volume of base required to get a certain $\mathrm{pH}$: In a titration between a weak acid $\ce{HA}$ and weak base $\ce{B}$ (adding base into acid solution) the ...
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0answers
29 views

Determining the composition of basic copper sulfate by titrimetry

A colleague shared an undergraduate level classical gravimetry/titrimetry experiment on determining the stoichiometry of basic copper sulfate. I am looking for a reference for this type of experiment. ...
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1answer
264 views

Finding the concentration of hydrochloric acid by titration

In a class experiment, $\pu{20 mL}$ of hydrochloric acid was diluted with distilled water to $\pu{500 mL}$. $\pu{20 mL}$ of this diluted solution was added to $\pu{20 mL}$ of $\pu{0.1 M}$ sodium ...
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2answers
915 views

What are the limitations of the Hendersson-Hasselbalch equation?

Our instructor told us that prior to the equivalence point, the $\mathrm{pH}$ of a solution is dependent on the HH equation. However, when I tried practicing for polyprotic acid titration, I came upon ...
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1answer
51 views

How a titration curve is affected when a poorly soluble salt is formed?

Suppose that I have $\pu{100 mL}$ solution of strong acid, $\ce{HA}$, at $\pu{0.10 mol L^{-1}}$. This solution is titrated with a strong base solution, $\ce{BOH}$, at $\pu{0.10 mol L^{-1}}$. Suppose ...
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3answers
566 views

How would a pH curve look like for titration of diluted weak base compared to concentrated one?

Let's say I take $\pu{80 g}$ of a weak base, dilute it with $\pu{50 ml}$ of water and titrate it with a strong acid. I get a titration curve. Now I take again $\pu{80 g}$ of the same weak base but ...
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0answers
22 views

How to prevent creation of piranha solution when conducting hydrogen peroxide titration?

I'm testing the activity of horseradish peroxidase (HRP) under different conditions by measuring the change in concentration of hydrogen peroxide substrate after a given amount of time. To stop the ...
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2answers
706 views

How to calculate the concentration of conjugate acid from given pH and pKa values?

Preface: Buffer solution (acid-base buffer). I am provided with a weak base, which I will designate B. $\mathrm{p}K_\mathrm{a}$ for $\ce{B}$'s conjugate acid, which I will designate $\ce{BH}$, is $8.1$...
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2answers
1k views

Error propagation Titration

I hope I am right in this section. I am unsure with error propagation. When calculation the error in a titration, many errors has to be taken into account: Error in Glassware/ Error in Balance/ ...
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0answers
43 views

Using concentrated sulfuric or nitric acid during titration of permanganate with oxalic acid

During titration of $\ce{KMnO4}$ with $\ce{H2C2O4}$, can we use concentrated $\ce{H2SO4}$ or $\ce{HNO3}$ instead of bench sulfuric acid?
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1answer
69 views

Titration of barium(II) hydroxide by hydrochloric acid

$\pu{25 ml}$ of $\pu{0.024 M}$ $\ce{HCl}$ is titrated into a volumetric flask which initially contains $\pu{45 ml}$ of $\pu{0.034 M}$ $\ce{Ba(OH)2}$. Calculate the $\mathrm{pH}$. This is how I ...
2
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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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0answers
30 views

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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2answers
2k views

Why are synthetic pH indicators used over natural indicators?

Synthetic indicators seem to be exclusively used when determining the pH of a substance with an indicator (with the exception of that school experiment where you boil cabbage to demonstrate natural pH ...
0
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1answer
348 views

Titration of aspirin

I have performed an experiment to test how temperature affects how fast aspirin dissolves by titrating solutions at various time intervals. According to this website, aspirin reacts with water as such:...
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1answer
47 views

Redox titration or iron(II)

The concentration of $\ce{Fe^2+(aq)}$ can be determined by a redox titration using A. $\ce{KBr}$ B. $\ce{SnCl2}$ C. $\ce{KMnO4}$ (basic) D. $\ce{KBrO3}$ (acidic) Can anyone please ...
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1answer
163 views

Calculating pH when weak base is added to an strong acid

$\ce{NH3}$ solution of $\pu{0.1 mol dm-3}$ is being added to a $\pu{25.0 cm3}$ of $\pu{0.1 mol dm-3}$ $\ce{HCl}$ solution. Calculate the pH of the solution when volume of added $\ce{NH3}$ solution is $...
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4answers
119k 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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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
503 views

How to calculate the equivalent mass of Na2S2O3? [closed]

Let us consider the following reaction $$\ce{I2 + 2 Na2S2O3 -> 2 NaI + Na2S4O6}$$ Now, in order to calculate the equivalent mass of $\ce{Na2S2O3}$, first I need to calculate it's $n$-factor which ...
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1answer
986 views

How to calculate the equivalent weight of KMnO4?

Let us consider the following reaction $$\ce{2 KMnO4 + 16 HCl → 2 KCl + 2 MnCl2 + 8 H2O + 5 Cl2}$$ Now, in order to calculate the equivalent mass of $\ce{KMnO4}$, first I need to calculate it's $n$-...
1
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1answer
35 views

pKa and equivalence point [closed]

I was doing a titration and using $\ce{NaOH}$ as the titrant. The analyte was a weak acid with a $\mathrm{p}K_\mathrm{a}$ of 4.90. Today I want to use another acid with a $\mathrm{p}K_\mathrm{a}$ of 4....
1
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1answer
110 views

Calculating the ph of an unknown solution by measuring the precipitate [closed]

You have an unknown metal hydroxide, but no meters or indicators. You have lead (II) nitrate, which is soluble in it, and lead (II) hydroxide that is insoluble in it. You take one liter of the unknown ...
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1answer
40 views

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{...
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1answer
37 views

Could this solution be resolved by titration?

I have a mixture of $\ce{NH_4NO_3}$ and $\ce{NH_3}$ at $\ce{pH}$ of about 13. It is possible to determine the concentration of both on them by acid-base titration? I was told it's possible, and that ...
0
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1answer
108 views

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 ...
2
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0answers
483 views

How to calculate the composition of a mixture of iron oxides containing inert impurities with titration data?

An $\pu{8 g}$ sample of $\ce{Fe3O4}$ and $\ce{Fe2O3}$ containing some inert impurity was treated with excess of aqueous $\ce{KI}$ in acidic medium, which converted all iron to $\ce{Fe^2+}$. The ...
0
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0answers
101 views

Can sodium carbonate-sodium bicarbonate buffer be used for EDTA titration of calcium?

I am planning to measure general/total hardness (calcium and magnesium) of aquarium water using EDTA titration with Eriochrome Black T indicator. From what I understand, the unknown solution must be ...
1
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1answer
44 views

Diluting a sample of weak base before titration. What happens to equivalence point pH of diluted vs undiluted?

A student titrated a 10.00 mL of 0.20 M methylamine ($\ce{CH3NH2}$) and determined that 10.00 mL of $\ce{HCl}$ was needed to reach the equivalence point. If you diluted your original sample of ...