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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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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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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Lab Methods for Determination of Phosphoric Acid Concentration

Dear stack exchange, For my next lab session we have been tasked to come up with two different methods for determining the concentration of an unknown sample of phosphoric acid. Design at least ...
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Is the following procedure for antacid titration correct? [closed]

I'm trying to check which antacid is more effective by determining the amount of $\ce{HCl}$ they can neutralize. Take $\pu{10 mL}$ antacid suspension and add excess $\pu{1 M}$ $\ce{HCl}$. Back ...
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calculating ph of a mixture of acids

I came across a question that couldn't find the answer to and i couldn't find the answer anywhere. The question is the following. You have a soltion created by dissolving HCN and HBrO in water (T = ...
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Substitute for alkali-iodide-azide reagent for BOD test of water samples

To measure the biological oxygen demand (BOD) of water samples, I am following a procedure that uses manganese sulphate, $\ce{H2SO4}$, and titration with standard sodium thiosulfate solution. Alkali-...
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How do you experimentally calculate the ionization constant of the carbonate ion?

Given sodium hydrogen carbonate, $\ce{NaHCO3}$, as well as hydrochloric acid, $\ce{HCl}$, how would you experimentally determine the ionization constant for the carbonate ion, $\ce{HCO3-}$? By ...
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How much additional hydrochloric acid should be added to arrive at ‘excess acid’?

I am an IB student. And I am trying to find the mass percentage of $\ce{NaHCO3}$ in antacid. I am dissolving the antacid in $\pu{0.1 M}$ $\ce{HCl}$ solution. So, first of all I conducted some ...
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Hacking a pH meter and digital burette to partially automate a titration [closed]

This is a chemistry question about experimental techniques and technology. I would like to connect a digital burette (Brand Titrette) and a pH meter to a computer and automate data acquisition to ...
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Why the colour of KMnO4 at the end point of titration may disappear after some time?

In the redox titration of $\ce{FeSO4}$ with $\ce{KMnO4}$, the colour change of the solution at the end point is colourless to light pink. Most laboratory manuals and books advice us to check whether ...
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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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What is the product of the titration of potassium permanganate and iron(II) sulfate?

I recently did an experiment at school, where I had to titrate KMnO4 with FeSO4. The solution was colourless, then turned yellowish until the end point was reached and it turned pink in one drop. ...
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Colour change acid-base titration

I titrated orange juice with NaOH. I used no indicator, but at around the point of inflection, the juice changed colour to a more mustard-ish colour. What is the reason for this colour change?
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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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What primary standard acid can be used to standardise NaOH solutions by titration?

I've done an experiment to standardise $\ce{NaOH}$ using oxalic acid. What other primary standard acid can be used to standardise $\ce{NaOH}$? Can $\ce{HCl, H2SO4, HNO3}$ be used? I read up and ...
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Why is double my half-equivalence point not equal to my equivalence point?

Tris pKA = 8, therefore at pH = 8, the volume is 4.5mL. However the equivalence point simply can't be at 9mL, looking at this graph. It should be between approximately 9.5 and 10.5, no?
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How can a conductivity meter be used to determine the equivalence point?

I know how a conductivity meter works. Power is supplied to electrodes and these electrodes change charge. The ions in the solution will be attracted to the oppositely charged electrode. The charge ...
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1answer
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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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When titrating a weak acid should only undissociated acid molecules be considered?

Let's say we do the titration of a weak acid (acetic acid in this case) and a strong base (sodium hydroxide) represented by the following equation: $$\ce{CH3COOH + NaOH -> CH3COONa + H2O}$$ My ...
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Hardness of water using EDTA calculation issue

I have been asked to work out the hardness of water in German degrees and this is what I did: I got a sample of water I didn’t measure how much I put into my volumetric flask perhaps it was $\pu{8....
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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 ...
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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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Titration with Ca(OH)2

In the laboratory, $20.0$ milliliters of an aqueous solution of calcium hydroxide, $\ce{Ca(OH)2}$, was used in a titration. A drop of phenolphthalein was added to it to indicate the end point. The ...
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Questions on concentration [closed]

Currently I am attempting two questions on concentration but I am not sure if I am correct. Can someone help me with these questions? These are the questions: 1) Calculate the volume of pure water ...
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Determining the calcium content in cashews via titration?

I have been planning on an experiment for quite some time now (as part of my after-school chemistry club), but I still feel like I am missing something. Due to my family's calcium deficiency, I ...
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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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What is the role of the sulfuric acid in a titration between potassium permaganate and iron ammonium sulphate solution?

So basically my titration was of finding the concentration of potassium permaganate against an iron ammonium solution. In the iron ammonium sulphate solution it consisted of water, iron ammonium ...
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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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Could An Equivalence Point Be Calculated or Deduced Based on Limited Data with Accuracy?

I have recently been tackling a problem from one of my A-Level chemistry exercises on the topic of acids and bases, particularly with strong base and weak acid titration curves: A titration is ...
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Weighing by difference

When preparing a known mass of something (e.g. when producing a standard solution) it is often that in my school lab that we first use a weighing boat to measure the mass and then once transferred ...
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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 ...
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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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Saponification Value of a fat/oil

The saponification value of a fat was determined by adding $\pu{9.0 g}$ of the fat to flask containing $\pu{50.0 cm3}$ of $\pu{1.00 M}$ ethanolic potassium hydroxide. The remaining solution was ...
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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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What is causing the buffer region in a weak acid - strong base titration?

For the buffer region in this, why does it stop the pH from increasing? At the start: $$\ce{CH3COOH + NaOH -> CH3COONa + H2O}$$ Which means there will be a high amount of salt in the solution, ...
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How do I determine which is the reduction reaction in a hydrogen peroxide and potassium permanganate solution?

How was it determined that $\ce{MnO4-}$ was reduction, and $\ce{H2O2}$ was oxidation? Also, why wasn’t the equation $$\ce{MnO4- + 2H2O + 3e- -> MnO2 +4OH-}$$ used? Or the $$\ce{H2O2 + 2H+ +2e- -&...
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How to correctly prepare a standard solution?

Having just spoken to my teacher about the creation of a standard solution, and she suggested one way of doing it, however a previous chemistry teacher had told us a different way of doing it. My ...
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Is this enough information to solve this problem?

Calculate the volume of a $\pu{0.100M}$ solution of $\ce{HNO2}$ and the volume of a $\pu{0.200M}$ solution of $\ce{NaNO2}$, that must be mixed to prepare $\pu{300ml}$ of a solution with a $\mathrm{pH=...
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How is the the law of chemical equivalence defined and what are its limitations?

I've heard that the law of chemical equivalence states that the gram equivalence of each of the reactants equals the gram equivalence of each of the products. But I'm facing difficulties in ...
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In a mixture of NaOH and Na2CO3, why doesn't phenolpthalein change its color until Na2CO3 is half neutralised?

Let us consider a mixture of $\ce{NaOH}$ and $\ce{Na2CO3}$. Based on what I have understood, double titration works in the below manner : Phenolpthalein turns pink when added to the mixture. As $\...
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Titration - Just need your judgement

A student investigated the volume of sulfuric acid that reacted with 25 cm3 sodium hydroxide. Describe a titration method the student could use in this investigation. {6 marks} My answer: Use the ...
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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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Formula for finding how much base to add to buffer to obtain a desired pH

Given: molarity and volume of the weak acid, molarity of the strong base, desired $\ce{pH}$, $K_{a}$ of the acid. I tried coming up with a formula to solve for the amount of base to add in order to ...
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How can the standard deviation for a set of experimental value be interpreted in terms of precision?

I have read from many websites that the sample standard deviation can be used to measure the precision of experimental values. I understand that the lower the standard deviation the better, as it ...
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Why titrating strong base with weak acid doesn't end at pH 7? [duplicate]

If I understand this titration correctly, if we titrated 50mL 1.00M acetic acid with 1.00M NaOH, the equivalence point would happen at a pH greater than 7, and less than 50mL of NaOH would need to be ...
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How to Prepare a 80mL Carbonic Acid-Bicarbonate buffer solution of ph=7.4 in laboratory? [closed]

I have the following materials which I can use: 0.1 M sodium bicarbonate solution Sodium Bicarbonate powder 0.1 M HCL Distilled Water Universal Indicator It will be a great help if you can provide ...
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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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Why does a titration have to be precise?

When we do titrations (w/ phenolphthalein) in lab, I know it's fun to see how close we can get the solution to clear, but why does my teacher place so much emphasis on accuracy and criticize ...
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Is the amount of substance of acid and base always equal at the equivalence point?

Does the amount of substance of acid always have to equal the amount of substance of base at the equivalence point? I know it "works" for monoprotic acids and monobasic bases, but what if we had a ...
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Redox Titrations Half & Full Equations

I was presented with the following problem and I am finding it difficult to present the half equations for the answers. I managed to produce the half-equation for the Iodine redox. $\ce{2I- -> ...