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### Topic: What titrations have you tried?  (Read 130088 times)

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#### Borek

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##### Re: What titrations have you tried?
« Reply #30 on: April 03, 2009, 09:00:03 AM »
Determining salt content in dried soup powder by Potentiometric Titration.

Titrant AgNO3 (0.1M)

That's not (kitchen) salt determination, that's chlorides determination (or, more precisely, sum of chlorides, bromides and iodides).

Quote
Manufacturer spec only gives sodium content, than NaCl. A trick often played by corporations!

It is sodium that has to be controlled in your diet. Where is the trick?
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#### Fridushka

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##### Re: What titrations have you tried?
« Reply #31 on: August 30, 2009, 07:43:51 PM »
precipitation titration: preparation and standardization of silver nitrate and potassium thiocyanate solution and determination of chloride in an unknown sample.
We used Fajnas and Mohr methods and got the average [Ag+]=0.106665 mol/L
after which we find the mCl-= 0.06247g
the [SCN-]= 0.10602 mol/L
then we used Volhard method to determine the %Cl in the unknown sample which was equal to 52.74%

Complexation Titration: preaparation and standadization of EDTA solution, & determination of total Hardness of water.
1st of all, we calculated the average concetration of EDTA=  9.2x10-3 then we found the [CaCO3]=0.001160701 mol/L, and we got the its mass to be equal to ~ 11.62 mg

Redox titration: preparation and standadizationv of a potassium permaganate solution and determination of the percentage of Oxalate in an unkown sample.
[Mno4-]=0.018M, while the oxalte; [C2O42-]= 0.0179M
then we get the %C2O42-=48.513% with an error of + or - 4!

#### Ida Isotope

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##### Re: What titrations have you tried?
« Reply #32 on: August 31, 2009, 10:29:46 AM »
Off the top of my head I recall using potassium permanganate alot. As well as HCl and NaOH.

#### blurry

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##### Re: What titrations have you tried?
« Reply #33 on: February 07, 2010, 06:57:03 AM »
finding amount of sugar in apple juice

finding number of moles of NaOH needed to neutralize HCl

finding amount of CaCO3 in an eggshell

analysis of aspirin tablet

standardization of potassium hydrogenphthalate and using it in order to determine concentration of a solution of NaOH

determination of the relative molecular mass of a group 2 carbonate.

i must say the actual experiment is quite fun, but the calculations are rather annoying. and im still in high school! cant imagine what uni will be like.

#### Golden_4_Life

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##### Re: What titrations have you tried?/ZnO
« Reply #34 on: August 06, 2010, 11:32:14 AM »
We titrated 3 times a sample of diaper rash cream that was labelled as "20.5% ZnO", our results indicated tha the cream had 30.1% ZnO.  The method we used was USP (with  inidcator =eriochrome black t.s. and chelator = EDTA).
1) why would such a disparity in quants be observed?
2) could the product label value be wrong?
3) we believe our assay is valid as it was "method validated" but only to 5% wt. ZnO.
4) but regardless, isn't it a linear assay up to and way above 5% anyway? So, the same assay should work for a 20% conc. level no?

Thanks in advance for any insights,
G-4-L.
Golden4Life

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##### Re: What titrations have you tried?
« Reply #35 on: September 30, 2010, 04:35:51 PM »
First of all: sorry bad English

I have tried different tipologies of titrations:
1-Ordinary standardization of a strong acid (HCl,with sodium carbonate) and a strong base (NaOH,with  acid phtalate of potassium).When titrated HCl with NaOH, we had to show graphically the effect on the titration curve of the difference of concentration between acid and base.

Titrations I like very much:
2-Titration of the % of acetic acid in vinegar- White vinegar to see a better colour change.
3-Titration of dissolved O2 in river and lake water by Winkler method.Difficult add reagents to glassworks.
4-Potentiometric titration of Fe2+ to Fe3+ with KMnO4
5-Fajans quantitative determination of chloryde ions - Difficult to see change of colour
6-Quantitative determination of Ca2+ and Mg2+ simultaneously by complexometric titration with EDTA
7-Titration to calculate the pKa1 and pKa2 value of aspartic acid
8-Titration of H2O2 with iodometric titration - less interferences in comparison with mangametric
9-Iron determination by Zimmermann titration
10-Titration  of carbonate-bicarbonate mixture
11-Conductometric titration of Cl- with solid electrode-

Sometimes difficult to built curve and calculate final point with "Gran Method" for weak acids or different graph methods of determianation.I like titrations very much.
Nowadays analytical chemistry seems to be only instrumental analysis..but i feel chemistry in titration =))

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##### Re: What titrations have you tried?
« Reply #36 on: December 16, 2010, 12:25:08 PM »
I have done, Acid- Base + Redox, Iodometric, Iodimetric, Complexo metric, Non aqous and  cloulomtric titrations.

#### sschoe2

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##### Re: What titrations have you tried?
« Reply #37 on: April 29, 2013, 04:03:27 PM »
I've done countless titrations as a TA for gen chem and also at my job.

My most frequent titration I do today is titration Cl- ions with AgNO3. To determine the salt content in foods it is dissolved in acidic water and AgNO3 is added. It reacts with the Cl- ions to form insoluble AgCl and with the removal of the Cl- from the water the conductivity of the solution is reduced which is detected by an electrode in the solution.

I also frequently titrate weak acids like malic with NaOH to get total acidity.

Another interesting one is the titration of ethanol with Cr (IV).
http://www.chem.uic.edu/chem114/LAB/ethanol_oxidation.pdf
it was a undergrad lab in kinetics when I taught but for all you boozers it is the basis for Breathilizers used by cops.

#### mohsendm

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##### Re: What titrations have you tried?
« Reply #38 on: July 17, 2013, 04:57:14 AM »
titration HCL with NaOH to determinate PH.

#### 408

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##### Re: What titrations have you tried?
« Reply #39 on: July 17, 2013, 02:06:12 PM »
Hypofluorous acid with thiosulfate and iodide to determine concentration.

#### sarahbarkson

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##### Re: What titrations have you tried?
« Reply #40 on: July 21, 2013, 09:12:59 AM »
neutralisations

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##### Re: What titrations have you tried?
« Reply #41 on: February 15, 2014, 05:51:19 PM »
Hi
Paper or electronic form  ?

#### Borek

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##### Re: What titrations have you tried?
« Reply #42 on: February 16, 2014, 03:35:10 AM »
The real thing only.
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#### Xenonman

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##### Re: What titrations have you tried?
« Reply #43 on: April 08, 2014, 10:30:54 PM »
The usual NaOH and HCl ones. I think I've done most of those correctly.
Na2CO3 with HCl and H2In+Methyl red. That one was horrible  the color change wasn't what I expected.  A mess.
Iodine-in-cleaning-products titration with sulphite and starch. That was the best one. One drop changed the solution from pitch-black to transparent.
Boric acid and mannitol made a weird, monoprotic complex which removed all the fun. We even used H2In again. No new reaction, no new indicator, no new colors. That could have been any other acid and we'd never have known.
Volhard and Mohr's. We all expected a blood red color for the end point because the procedure said that. Turns out the the end point has a faint orange color, not a blood red one. Mohr's was much friendlier.
Honeste vivere, alterum non laedere, suum cuique tribuere.

#### cseil

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##### Re: What titrations have you tried?
« Reply #44 on: August 17, 2014, 07:35:35 AM »
I don't have the results (I'm not home right now).
I did these titrations during the course of Analytical Chemistry I.

Acid-base

NaOH with KHP
HCl with C4H11NO3
Determination of the percentage of HCO3- and CO32- into a solid mixture (unknown)

Complexometry

Na2H2EDTA with CaCO3
Determination of the percentage of Ca2+ and Mg2+ into a sample of mineral water

Precipitation

AgNO3 with NaCl
Determination of the concentration of Cl- into a sample of water (Mohr's method)
KSCN with AgNO3
Determination of the concentration of Cl- into a sample of water (Volhard's method)

Redox

KMnO4 with Na2C2O4
Determination of the percentage of H2O2 into a disinfectant (I used KMnO4)
Na2S2O3 with K2Cr2O7
KMnO4 with Na2S2O3 (iodometric)
Determination of NaOCl into a sample of bleach for domestic use
Determination of the percentage of ascorbic acid into a nutritional supplement