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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Redox reaction KMnO4 + FeX [closed]

Today I was conducting a redox titration with $\ce{MnO4}$ and unknown amount of $\ce{FeX}$ which through qualitative observation looked like $\ce{FeO(s)}$. I titrated the $\ce{FeX}$(which was ...
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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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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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425 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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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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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 ...
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608 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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628 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 curve of strong acid with strong base [duplicate]

I have a question regarding the titration curve for $\ce{HCl}$ titrated with $\ce{NaOH}$. Why does it look like it does, with a steep slope near the equivalence point and a flat slope at the beginning ...
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pH calculation - adding distilled water after titration [closed]

Will someone help me figure out how can I solve the following question? We are given 110 ml of acetic acid (pKa=4.76), with concentration of 1M, to which we add 10 ml of NaOH with concentration of ...
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121 views

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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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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209 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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918 views

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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Titration of H3PO4 with NaOH

I came across an ionic equilibrium problem stating: Find the pH when 150 ml 1 M $\ce{NaOH}$ has been added to 100 ml 1 M $\ce{H3PO4}$. I'm stuck with this question. What I know: $$\ce{H3PO4 + NaOH ...
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11k views

Finding molar mass of an unknown acid

"In the titration of a solid acid, an endpoint is reached after 22.0mL of 0.120 M $\ce{NaOH}$ has been added. Assuming that each acid particle contains two acidic hydrogens and both are ...
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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 ...
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2k views

Oxidation of sodium thiosulfate by iodine

When $\ce{Na2S2O3}$ reacts with $\ce{I2}$, it undergoes a redox reaction as $$\ce{2 Na2S2O3 + I2 -> Na2S4O6 + 2 NaI}$$ Sulfur is being oxidized from a $+2$ state to a $+2.5$ state. Why isn't it ...
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5k views

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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365 views

Writing equation of reaction in stoichiometry of redox titrations

While solving some questions on the stoichiometry on redox titrations, I come across this question: Calculate the volume of $0.05\ \mathrm{M} \ \ce{KMnO4}$ solution required to oxidize completely $...
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Titration of H2SO4 w NaOH: Solving for the molarity of H2SO4?

I am given $\ce{H2SO4}$ in a reaction vessel of about $50~\mathrm{mL}$. I need to solve for the molarity of $\ce{H2SO4}$. A $10~\mathrm{mL}$ sample of $\ce{H2SO4}$ is removed and then titrated with $...
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48 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 ...
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3k views

When using a “dilute hydrochloric acid” solution, how diluted should it be?

Quite often when reading through some instructions or documentation or an outline that I've found online (EG: acid-base extractions), theres a step that involves using a "dilute hydrochloric acid ...
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1k views

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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118 views

How to find pH in the following titration/buffer problem given concentration of base and acid

A $100. \text{ mL}$ sample of $0.10 \text{M } \ce{HCl}$ is mixed with $50. \text{ mL of } 0.11 \text{M } \ce{NH3}$. What is the resulting pH? (Kb for $\ce{NH3} = 1.8 × 10–5$) I was thinking more ...
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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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886 views

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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3k views

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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1k views

Law of chemical equivalence

In this reaction, $$\ce{KIO_3 + KI -> I_2}$$ According to law of chemical equivalence, shouldn't $m_{eq}$ of $\ce{KIO_3}$ = $m_{eq}$ of $\ce{KI}$ = $m_{eq}$ of $\ce{I_2}$? However, the book that I ...
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112 views

Including H⁺ from the dissociation of the acid in a titration pH calculation?

Let's say you are doing a standard titration problem, for example: Find the pH after adding $10~\mathrm{mL}$ of $0.3~\mathrm{M}$ $\ce{NaOH}$ in the titration of $25~\mathrm{mL}$ of $0.3~\mathrm{M}...
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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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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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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 ...
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58 views

Acid value of linseed oil

For this we weigh $\pu{1.015 g}$ of linseed oil which is dissolved in alcohol. 3 drops of phenolphthalein (pH indicator) are added and a solution of potassium hydroxide of concentration $C = \pu{9.5e-...
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632 views

Why is sulphuric acid added in the ripper titration?

Ripper titration can be used to determine free $\ce{SO2}$ in wine by titration with iodine. The method requires sulphuric acid to be added to wine before titration. Why is this the case?
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7k views

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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866 views

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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464 views

What indicators can be used when substituting iodine with other halogens in the Winkler method?

I'm a chemistry student who is doing an investigation with respect to the Winkler method. The Winkler method is one which is used to find the oxygen content in water. Primarily, the halide which is ...
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416 views

How to do complexometry titration of calcium oxalate?

My titration of calcium oxalate with NaEDTA doesn't work. I need to calculate the ion calcium within my sample. My essay is to test anticalculi activity. Why do I say I have problem? Because the ...
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3k views

How does standardising a secondary standard solution make it suitable as a standard solution?

I know that a standard solution in volumetric analysis must have an accurately known solution. Primary standard solutions (e.g. anhydrous sodium carbonate) can be used straight-away as they follow the ...
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570 views

Does CO2 dissolution in different salt concentrations affects the amount of carbonic acid formed?

We have a school experiment, where I must report on the following question: Does salinity affect the solubility of $\ce{CO2}$ in saltwater? So we selected four different concentrations of salt (...
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433 views

Properties of Polyprotic acids?

I have a graph of a titration of a weak polyprotic acid with a strong base. I graphed $p\ce H$ versus amount of strong base added. Now since the acid is polyprotic, how do I determine which ...
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Nicotine concentration in e-liquids

E-liquids are blends of nicotine, propylene glycol, vegetable glycerin, and aroma. I need to develop a method for determining the concentration of nicotine in a vial. (to verify if the information ...
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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 ...
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161 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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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....
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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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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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861 views

Precipitation titration with Volhard method

In the Vollhard method Chloride is precipitated from a solution using escess silver ions. $$\ce{Ag+_{(aq)} + Cl-_{(aq)} -> AgCl_{(s)}}$$ After precipitation the solution is filtered and ammonium ...