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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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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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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7k 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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187 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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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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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 ...
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270 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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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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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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299 views

Identifying a polyprotic acid using titration

I have the following question from a high school chemistry lab: If an unknown acid has more than one equivalence point, is there a reason to expect a specific $K_\mathrm{a}$ ($K_{\mathrm{a1}}$, $K_{...
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Titration curve, how to find equivalence point

If you have a graphed titration curve and have points near the equivalence point like 6.85 pH at 54.60mL titrant added and 8.01 pH at 54.73mL titrant added is there any good way to find a more ...
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427 views

What concentration (M) of citric acid should I use in a titration with 0.02M LiOH?

I am using an automatic titrator that records the amount of acid/base added and the pH of the solution in the form of a graph. I am trying to titrate citric acid to capture all 3 pKas in this graph. I ...
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Concentration of NaIO3 using hypo

$$\ce{2NaIO3 + 5NaHSO3 -> 3NaHSO4 + H2O + I2 + Na2SO4}$$ $\mathrm{20ml}$ of $\ce{NaIO3}$ solution reacted with excess $\ce{NaHSO3}$ releasing $\ce{I2}$ that can oxidize $\mathrm{20ml}$ of $\...
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176 views

How to calculate amount of nonanoic acid needed to prepare sodium nonanoate salt

I have this procedure for making sodium heptanoate, but I need to adapt it to make sodium nonanoate. The protocol is as following: Dissolve $\ce{NaOH}$ in pure ethanol After all $\ce{NaOH}$ has ...
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495 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 ...
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637 views

Absorbance vs titrant added in acid-base titration

I was working on this question: Nitrophenol is a colorless weak monoprotic acid ($\mathrm{p}K_\mathrm{a} = 7.2$) whose conjugate base is bright yellow. To $2.00\ \mathrm{mL}$ of a solution of $...
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635 views

Buffer capacity of different types of milk

Currently I am tasked with designing an experiment that that I will have to perform in 2-4 weeks, but I don't have to decide on on a topic soon. I was thinking of performing an acidometric titration (...
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Titration of alpha-amino acid with strong base

Question: $\mathrm{50~ml}$ of the conjugate acid $\ce{H3N+CH(R)COOH}$ of an $\alpha$-amino acid required $\mathrm{30~ml}$ of $\mathrm{0.1~M}~\ce{NaOH}$ to completely convert into the dipolar ion $\ce{...
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56 views

Is there a way to cheaply transfer (plunge by pushing) a viscous liquid in to another container without plunger-to-tube discharge?

Could anyone offer a suggestion as to how an economy-minded chemist ought to implement a DIY-ed positive displacement alternative to the following:
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Iodometric Titration: Would iodine react with sucrose as well?

I'm currently planning to do a lab experiment about the effect of sugar addition (sucrose) to orange juice on Vitamin C (ascorbic acid), also finding the degradation rate and activation energy ...
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45 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 ...
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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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28 views

How can a titration help me figure out the effect of rosmarinic acid on amylase activity?

So with my limited knowledge of rosmarinic acid, I am aware that it is an non-competitive inhibitor and can inhibit the enzyme, amylase. When starch is added to a solution of already mixed rosmarinic ...
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287 views

Eriochrome Black T titration - Concentration of Indicator and endpoint

While not as frustrating an indicator as murexide, Eriochrome Black T's wine red to blue transformations provide significant challenges. The change from "fully wine red" to "fully blue with no trace ...
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191 views

Iodometric Titration - Iodine Crystal formation

During an iodometric titration iodide is oxidised to iodine by an oxidiser, and then titrated using standardised sodium thiosulfate. I have had no problems using iodate as the oxidiser, however, using ...
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33 views

Titration curves

If I were to model the titration of $30 \ \text{cm}^{3}$ of $ 3 \ \text{mol dm}^{-3}$ $\ce{CH3COOH_{(aq)}}$ with $3 \ \text{mol dm}^{-3}$ $\ce{NaOH_{(aq)}} $ , what would the equation look like (...
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What is the electrode potential at the equivalence point if concentrations of titrant and titrand are going to be zero?

Let's assume that the titrand is $\ce{Fe^2+}$ and the titrant is $\ce{Cr2O7^2-}$. Then $$E = E^\circ_\ce{Fe^{2+}/Fe^{3+}} - \frac{RT}{nF}\ln\frac{\ce{[Fe^{2+}]}}{\ce{[Fe^{3+}]}}$$ $$E = E^\circ_\ce{...
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204 views

Determining the chemical formula of a polyiodide Salt

I've got a compound with formula $\ce{N(CH3)4.I(I2)_x}$. By mass I've got $\pu{0.138 g}$ of $\ce{I2}$ present out of $\pu{0.189 g}$ of polyiodide added. How do I find $x$? This is the exact part of ...
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95 views

Is endpoint pH concentration dependent? Choosing an acid/base indicator

We use titrations to determine analyte concentrations with a standardized titrant and an acid/base indicator, BUT how do we choose the indicator? It is my understanding that indicators are supposed to ...
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317 views

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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333 views

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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269 views

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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904 views

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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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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712 views

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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128 views

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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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- -> ...
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Dichromate-thio titration

Can dichromate in acidic media be titrated directly with buffered thiosulfate solution using $\ce{H2O2}$ as an external indicator instead of using $\ce{KI}$ which is a standard procedure? $\ce{...
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312 views

How can you perform an acid-base titration with antacids if substances, like aluminium hydroxide, are insoluble?

I am trying to perform an experiment in order to determine the efficiency of different antacids. An online search later shows that you add an HCl solution in a solution created with a base/antacid. ...
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365 views

Precipitation of Calcium ions in basic Sodium Hydroxide solution?

I recently conducted an EDTA titration of milk to find its Calcium contents. I got a value significantly smaller than the theoretical value. (≈10 times smaller). I made $50ml$ samples to which I added ...
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711 views

Does the acid dissociation constant fluctuate or stay constant during titration?

I'm doing titration experiment, where I record the volume of base added and the pH value, then use these two variable to make a titration graph. I'm suppose to extrapolate any data needed from the ...
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656 views

How do I calculate the molecular mass of a complex in a complexometric titration with EDTA?

I had to titrate 0.35 mmol (3.2 g) of $\ce{Co2F2(Hdmpz)6(BF4)2}$ in a solution with 10 drops of 37 % $\ce{HCl}$, 10 mL of 4 M $\ce{NaOAc}$, 25 mL water and xylenol orange as indicator with a 0.05 M ...
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665 views

Indirect titration with ascorbic acid

We were doing a titration experiment to find out how much ascorbic acid a vitamin pill actually contains. In a flask, there is a solution of water, sulfuric acid, potassium iodide and ascorbic acid. ...
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421 views

How can I determine the pH of a solution when I add more analyte after the equivalence point?

In titrating 25 mL of a 0.2 M weak acid, HA, with 0.5 M of a strong base, say NaOH, the equivalence point is reached after 10 mL of base is added. I can calculate the pH by first setting up an ICE ...
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58 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 ...
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1answer
979 views

Iodine Titration with Free SO2 in wine

To determine the free $\ce{SO2}$ in wine, a common method used is called the Ripper Titration Method. The equation is as follows: $$\ce{SO2 (aq) + I2 (aq) + 2H2O (l) -> 4H+ (aq) + SO4^2- (aq) + ...
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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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33 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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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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45 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?