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 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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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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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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476 views

Strong Acid/Strong Base Titration

Bromothymol Blue is an indicator that turns yellow in acid, blue in base. If I were to titrate NaOH with HCl, what color should I look for at the equivalence point? Should I titrate until the ...
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How to read the used volume from a burette?

I conducted an acid-base titration with vinegar and sodium hydroxide today, where sodium hydroxide was used as the titrant (solution in the burette). I collected the data for the initial and final ...
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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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Why isn't an Acid-base titration curve linear? [duplicate]

Sorry if this is a stupid question, but why is a acid-base titration curve not linear? As you add more acid solution to a basic solution, shouldn't the pH of the basic solution slowly go up in ...
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Brown color at end point during titration with phenolphthalein as indicator

We did a titration experiment at school and I did not understand one part of it. The scenario: Titrate : White wine (ethanoic acid) Titrant: $\ce{NaOH}$ Indicator: Phenolphthalein What happened:...
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531 views

Fe 2+ and MnO4- titration?

As a lab experiment, I am preparing a mixture of iron tablets dissolved in sulfuric acid so they can be titrated against $\ce{MnO4-}$. The tablet contain insoluble filler material. Why is it ...
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How to prove at what pH the color of an indicator will change based on its pKa?

The equivalence point of an acid-base titration can be determined by choosing the appropriate colored indicator. This indicator is a weak acid $\ce{HA}$. The undissociated acid has a different color ...
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Getting the wrong pH value, according to data and online calculator

I'm doing a titration problem with a week acid and strong base, I used experiment data and an online calculator to check my answer, but my pH I calculated is a bit off. Can anyone see where I messed ...
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How to calculate the pH of soft drinks based on titration data? [closed]

Your enamel is composed of a calcium hydroxyphosphate ($\ce{Ca5(PO4)3OH}$), also known as mineral apatite. This “apatite” is slowly broken down into calcium phosphate and water as illustrated in the ...
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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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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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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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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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Calcium sulfate soluble in water

In the volumetric estimation of calcium in a given solution as calcium oxalate. We convert the calcium oxalate to oxalic acid by dissolving the former in hot (~70 °C) 2 N sulfuric acid solution. This ...
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How to determine the hydroxide ion concentration in an acidic aqueous solution?

When doing a titration with $\ce{HCl}$ and $\ce{NaOH}$, both being strong and dissociating completely, if you add a volume of $\ce{NaOH}$ that is less than needed to reach the equivalence point, you ...
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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 ...
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Titration curve graph, finding exact point of the equivalence point

I plotted all my data points and made this graph in excel. Now I need to find the volume of titrant required to read the equivalence point, as well as the pH after 18.5 mL of titrant have been added. ...
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419 views

Making a 10L HCl solution with 8.77% HCl in a 100 mL solution from a 16 M stock solution

How would you make 10L of HCl solution with 8.77% HCl in 100 mL from a 16M stock solution. Here's what I have tried so far: I put my percent HCl and got that down to match with the moles of HCl I ...
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Which method can be used to determine the pKa of an acid-base indicator like bromothymol blue?

I have a question about how one would determine the pKa of an acid-base indicator such as bromothymol blue. I know that spectrophotometric analysis is one option, but is it possible to perform an ...
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203 views

Concentration of a species outside buffer region (polyprotic acid titration)

I'm wondering if you titrate a polyprotic acid, say, $\ce{H3PO4}$, with a strong base, and you successfully pass the first equivalence point and are maybe at the $\mathrm{pH}=\mathrm{pK}_{a2}$ point ...
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Why does more acetic acid require more sodium hydroxide in order to be neutralized

I was recently titrating sodium hydroxide against vinegar and based off my results i realised that the vinegars with a higher concentration of acetic acid required more sodium hydroxide in order to ...
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Why is silver nitrate used for cyanide titration?

Or more to the point, since silver isn't exactly cheap: Why can't cuprous nitrate ($\ce{CuNO3}$) substitute for the pricier ($\ce{AgNO3}$) in cyanide titration? I assume that free cyanides bind ...
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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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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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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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Neutralization equation [closed]

If I have cider vinegar and want to calculate the total moles of acid found in it, how can I do it? I have the moles of NaOH and I know that it includes both acetic and malic acid but how can I ...
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How do I get the molarity of solution 1 given volume 1, molarity 2, and volume 2? [closed]

For example: What is the molarity of a $\ce{NaOH}$ solution if $25\rm~mL$ of the solution is exactly neutralized by $44\rm~mL$ of $0.32\rm~M~HCl$? I know that the abstract function is $$\text{...
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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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Why does phosphoric acid mask the colour of iron(III) complex in water?

In the redox titration of iron(III) with permanganate or dichromate, we use phosphoric(V) acid to "mask" the color of iron(III) because it interferes with the end point color change. What's the ...
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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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How to calculate the dissociation constant of a weak acid from the titration with a strong base?

Problem: A solution of an unknown weak acid of unknown concentration was titrated with a solution of a strong base of unknown concentration. During the titration, the pH after adding $\pu{2.00 mL}$ ...
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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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Fluctuation in pH reading on pH meter

I was conducting a titration of a saturated $\ce{Ca(OH)_2}$ solution against $\ce{HCl}$ using a pH meter (the kind with a glass electrode). At the beginning of the titration, the pH reading would drop ...
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Finding the percentage of pure CaCO3

I found this in a textbook; it seems that the question is poorly worded. It goes as follows: $1.5~\mathrm{g}$ of chalk were treated with $10~\mathrm{ml}$ of $4~\mathrm{N}$ $\ce{HCl}$. The chalk was ...
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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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Sodium carbonate titration in presence of phenolphthalein

Why phenolphthalein cannot show the endpoint for the complete titration of Na2CO3 with only phenolphthalein? What's the reason that we consider only half of the moles of sodium carbonate when ...
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Why is Borax used as a primary standard?

It's given in my book that borax is a useful primary standard for titrating against acids. I have heard that primary standard is a pure reagent and does not gain any weight by absorbing moisture. (...
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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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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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How to calculate the sufficient ratio of acid and corresponding base of the indicator that allows to clearly observe the endpoint of a titration?

Ram can see the purple colour of an acidic indicator below pH = 5.5 only and the blue colour only above pH = 8.5. How many times that of acidic form must the concentration of the basic form at least ...
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Determining the nature of common pH indicators (methyl orange) using Le Chatlier's principle

I got some good information about this topic yesterday, and I understood what I was told, but I have come up with a specific way of phrasing the problem I'm having. It is slightly different than ...
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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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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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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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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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Should titration stop at the intermediate color or a drop past the intermediate

Using Bromcresol green as an indicator, should one stop when the blue color changes to green or to yellow for more accurate results. Shouldn't one aim to get a green because its far closer to the end ...
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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, ...