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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
34k views

Calculating pH for titration of weak base with strong acid

Calculate the pH at the equivalence point for the titration of $\pu{0.130 M}$ methylamine ($\ce{CH3NH2}$) with $\pu{0.130 M}$ $\ce{HCl}$. The $K_\mathrm{b}$ of methylamine is ${5.0 \cdot 10^{–4}}$. ...
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1k views

What is the cost of 1.00 g of calcium ions as provided by this brand of dry milk?

A student determined the $\ce{Ca^{2+}}$ ion content in a sample of nonfat dry milk. For complete titration of the $\ce{Ca^{2+}}$ ion present, a sample weighting $1.483 ~\mathrm{g}$ required $41.33 ~\...
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159 views

Rationale for titant standardization in alkalinity measurements [ISO 9963-1:1994]

I work in a environmental chemistry laboratory and I will start to do some alkalinity measurements in my project. My research group is pretty big on following any and all standardization possible, ...
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1answer
148 views

Is this problem about acid-base titration wrong?

I wouldn't post mere 'problems' here normally, but I will hopefully be starting to give chemistry education to some 10-11-12th graders and I want to make sure that it is not I that has a problem but ...
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1answer
2k views

Shape of Weak-Strong Acid-Base Titration

I can understand why in any titration, the pH changes really quickly near the equivalent point. However, in a titration of either weak base-strong acid or weak acid-strong base, the weak acid/base ...
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2answers
1k views

Titration of borax solution homework

Please check to see if there is anything that I should fix. Also, please check to make sure that my significant figures are correct. I am going to try to make it look like how I wrote it and how the ...
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1answer
577 views

Error in Titration

When doing a titration with a burette, the error of the burette is usually $\pm 0.05\ \mathrm {ml}$, as we have to read two times on the burette (initial/final vol), the error will be $\pm 0.07\ \...
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Titration of caffeine using Iodine

I was trying to do an investigation on the variation of caffeine content with temperature. I used 6 Lipton yellow label tea bags (black tea) to brew the tea solution. Next, I perform the extraction of ...
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210 views

Possible causes for flawed results of an EDTA titration for the Ca content of milk

Earlier today I was trying to find the calcium content of different milks as a part of a school assignment. I used this setup as the basis for my experiment: I was using $\pu{0.1 M}$ EDTA solution ...
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1answer
338 views

Mathematical explanation of blank titration in Mohr method for argentometry

In my book it is written that in order to minimize systematic error in Mohr method for argentometry it is a common procedure to conduct a blank titration with $ \mathrm{Ag^+} $ against a $\mathrm{CrO_{...
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157 views

EDTA Titrations

I was doing some questions on EDTA titrations and was wondering how you actually derive the second equation here: $$\begin{align} α_{\ce{Y^4-}} &= \frac{[\ce{Y^4-}]}{[\ce{H6Y^2+}] + [\ce{H5Y+}] + ...
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Adjusting the ph of salicylic acid using sodium hydroxide

Question How many milliliters of $0.202\ \mathrm M$ NaOH should be added to $25.0\ \mathrm{mL}$ of $0.0233\ \mathrm M$ salicylic acid to adjust the $\mathrm{pH}$ to $3.50$? The answer from the ...
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1answer
934 views

Why is Lanthanum a “fluoride ion sensitive electrode” and hence used for measuring “flouride concentration”?

My chemistry text book says that "Atomic Absorption Spectrometry (AAS) can be used to determine the concentration of metal ions, but other methods must be used for anions. One convenient method is to ...
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2answers
555 views

How to calculate the oxidation state and the number of equivalents oxidized with YBa₂Cu₃O₇

I've hit some trouble with these calculations and need help sorting out confusion. In the lab we synthesized $\ce{YBa2Cu3O7}$, per the lab manual $\ce{Y, Ba, O}$ have the usual charges of +3, +2, and ...
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1answer
958 views

Differentiating between Titration, Buffer, diluted buffer, Deionized H₂O

I had a chemistry lab where we had to titrate three solutions with HCl, a buffer, a diluted buffer and deionized water. My partner and I didn't label the charts we made, so now I have to figure out ...
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2k views

What source of error in an acid-base titration could lead to a higher reading of the acid concentration?

Methanoic acid ($\ce{HCOOH}$) is found in stinging nettles. In an analysis of the concentration of methanoic acid in a solution extracted from nettles, the solution was titrated with a standard ...
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1answer
161 views

Is there an established procedure for titanium tetrachloride titration?

I’m attempting to do an aldol reaction with $\ce{TiCl4}$ as the catalyst. It worked well in the large scale ($100~\mathrm{mg}$) test system but not, so far, in my $5~\mathrm{mg}$ scale actual system. ...
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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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6k views

How to determine the iron content in spinach from a titration with permanganate solution?

I used titration to find the mass of iron in a $5~\mathrm{g}$ sample of spinach after leaving the spinach to soak in tap water for 5 different amount of times. I added $\ce{H2SO4}$ to the solution and ...
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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 ...
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514 views

Cobalt Oxalate / Potassium Permanganate Titration

My class just did a lab today where we mixed cobalt oxalate with $40~\mathrm{mL}$ of $\ce{H2SO4}$ and then titrated it with $\ce{KMnO4}$ (potassium permanganate). I need the mole ratio of cobalt ...
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684 views

Acid-base titration: Calculate pKa with only three values given

There's an unkown acid, diluted with an unknown amount of water and titrated with $\ce{NaOH}$. After adding $\pu{10.00 mL}$ $\ce{NaOH}$, a $\mathrm{pH}$ value of $4.65$ is measured. After ...
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27k views

Primary and secondary standard

Why are secondary standard solutions used in titrations? Why don't we always use primary standard solutions?
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353 views

pH Curves for Titrations

Why does the pH rapidly increase near the equivalence point during--why does the slope of the graph of a pH curve sharply increase around this area?
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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 ...
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1answer
139 views

Why would CuSO4-EDTA drops be used in Pb titrations?

We use CuSO4-EDTA drops (4) when preparing our lead titration samples for final titration by EDTA. What mechanism would there be for adding this to a titration? What benefit does it produce on Pb ...
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2answers
1k views

How does an acid prevents or discourges oxidation of iron?

In the titration of $\ce{KMnO4}$ with Mohr's salt, I have learned that sulphuric acid prevents oxidation of $\ce{Fe^2+}$ to $\ce{Fe^3+}$ in the solution before the actual titration. How does the acid ...
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2answers
981 views

Can Henderson-Hasselbalch equation be used to determine the pH of a solution when a strong base and a strong salt of that base stay together?

The following problem I have stated was not given to me as a homework. I have found this one in my textbook. I have solved it in my own way, but I'm not sure about the correctness of my procedure. I ...
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1answer
1k views

Minimising the formation of manganese dioxide in the titration of potassium permanganate

For a titration of potassium permanganate into a standard acidified solution of hydrated iron (II) ammonium sulfate, the solution seems to end up brown (due to the formation of manganese dioxide) ...
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1answer
158 views

Neutralisation and end point pH

So I just finished my final paper yesterday and I tried to attempt this 8 mark question. I am not sure how to do it. $25\,\mathrm{ml}$ of $0.5\,\%~\mathrm{w/v}$ lactic acid ($\ce{C3H6O3}$, ...
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1answer
610 views

What does “the magnesium salt of EDTA” mean?

I am attempting to prepare an ammonium chloride/ammonium hydroxide buffer solution ($\ce{pH}=10 \pm 0.1$) for titrating water hardness with calgamite and EDTA. In the 17th Edition of the Standard ...
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1answer
114 views

Why isn't there a third buffering zone in the pH curve of this titration?

I'm in chem 30 right now and we were learning about pH curves and buffering zones. I was looking at a question on the titration of $\ce{H3PO4}$ with $\ce{NaOH}$. The curve showed two qualitative ...
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1answer
350 views

How would one correct for a blank in a potentiometric titration?

I want to do a potentiometric titration with perchloric acid of a sample consisting of active drug (weak base) and two other components. Based on theory, I already know that these two other components ...
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2answers
126 views

Are titration, recrystallisation, functional group analysis, etc. outdated?

In modern chemistry, - pH meter, ion electrode, AES, HPLC, etc. replacing titration - HPLC replacing recrystallisation - IR and NMR replacing melting point analysis, derivative analysis, functional ...
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1answer
612 views

Titration of reducing sugars on honey

So I'm trying to figure out how to titrate the reducing sugars on honey without generating iodine. The reaction so far I think I could do is do a Fehling reaction with $\ce{Cu}^{2+}$and then back-...
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1answer
76 views

Titration of bases against HCl

Suppose I take three bases in a solution, $\ce{NaOH}$, $\ce{Na2CO3}$ and $\ce{NaHCO3}$, and I titrate this solution with $\ce{HCl}$. Since the strengths of the bases are different, does it mean that $\...
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1answer
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Determine Cu+2 and SO4-2 concentration using Potentiometry?

The title says it all. I've been researching as well but all I could come close was solid state ion selective electrodes. Could someone please help me out? There should be two methods(or one) to ...
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3answers
980 views

Anthocyanins as pH-indicators: stop the titration at red, purple or blue?

If you titrate some hydrogen bromide solution (0.1 M) to some sodium hydroxide in order to determine the exact concentration of hydrogen bromide (0.1 M), and you use anthocyanins as a pH indicator. ...
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1answer
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When an iodide/iodate solution is acidified with H2SO4 instead of thiosulfate, why should it be titrated immediately?

My class is currently performing a reaction to determine the oxidizing power (i.e. the amount of hypochlorite) of household bleach. The general process is as follows: Standardize thiosulfate to be ...
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1answer
591 views

How much lactose is there in milk (mechanism)?

Iodometric titration is sometimes used to find out how much lactose there is in milk. The overall oxidation reaction is written as follows. $$\ce{C12H22O11 + I2 + 3NaOH ->[\ce{CuSO4}]C12H21O12Na + ...
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2answers
281 views

How to determine the concentration of a base through indirect titration?

$5.267~\mathrm{g}$ of $\ce{Na2CO3}$ was dissolved in $250.00\ \mathrm{mL}$ of water. $10.00\ \mathrm{mL}$ of this solution was titrated with $\ce{HCl}$. The end-point occurred at $21.30\ \mathrm{mL}$. ...
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1answer
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Titration, finding the molarity of HCl

$25~\mathrm{mL}$ of $\ce{HCl}$ are titrated with $.104~\mathrm{M}$ $\ce{NaOH}$ solution. If $32.55~\mathrm{mL}$ of $\ce{NaOH}$ are required to standardize, what is the molarity of $\ce{HCl}$? This is ...
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1answer
2k views

NaOH solution not stable

$\ce{NaOH}$ solution can react with $\ce{CO2}$ to form sodium carbonate. Is there any other reason why $\ce{NaOH}$ solutions for accurate titrations cannot be stored for long (or the titre has to be ...
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1answer
5k views

Calculating molecular weight of an acid based on titration data

If $\pu{2.600 g}$ of a weak diprotic acid were dissolved in $\pu{100 mL}$ of distilled water and a $\pu{10 mL}$ aliquot of this solution required $\mathrm{21.60\ mL}$ of $\mathrm{0.1000\ M\ NaOH}$ to ...
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1answer
165 views

Stability constant of complexes

I know that this constant tells us the strength of the interaction between the metal and the ligand, so should it also mean that the higher the constant, the stable the complex ? I need to make sure ...
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1answer
33k views

Finding the percent of calcium carbonate in commercial antacid by using back titration

I'm an IB Chemistry student and I had to do a back titration lab where 1g of a powdered antacid tablet were mixed with 50mL 1M HCl, and the mixture was titrated using 0.2 M NaOH; the NaOH was to ...
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1answer
303 views

Does changing EDTA concentrations affect the amount of calcium ions in milk?

For my chemistry experiment I am titrating EDTA against milk to find out the concentration of calcium ions in milk. I will be using EriochromeT as the indicator. The lab tech said that if I use ...
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1answer
1k views

Titration with EDTA and Eriochrome black T

I have a titration of Calcium Ions with EDTA. When I reach a volume of 9.6mL I the liquid turns slightly blue and after that the more I add the bluer it becomes. Now at what point is my titration ...
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1answer
13k views

Why rinse flask with distilled water when the flask will be used for storing aliquots of HCl for titration?

In an experiment for standardisation of NaOH with titration, the lab manual instructed students to rinse conical flasks that were supposed to store 1mL aliquots of hydrochloric acid with distilled ...
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1answer
769 views

How does dilution affect result of titration of jam?

We currently do some pH adjustments of jams (target pH of 3.2) using citric acid, however, when there is a large difference between the starting pH and the target pH this can be quite a time consuming ...