Iodimetry is a titration technique used to determine the amount of a reductant (substance being titrated) using a standardized iodine solution as the oxidizing titrant. The reductant is oxidized by iodine in a redox reaction. Iodimetry is performed under neutral or weak acid conditions to avoid the disproportionation or oxidation of iodine. Common indicators used include starch solution or carbon tetrachloride.
Acid base and salt class 10 science|| what are indicatorsPromilabis
In this particular presentation you will learn about acid base and slats along with them you will also learn about what are indicators and what are various types of indicators
Acid base and salt class 10 science|| what are indicatorsPromilabis
In this particular presentation you will learn about acid base and slats along with them you will also learn about what are indicators and what are various types of indicators
Iodometric titration cannot be doine at higher pH.pdfKARTIKINDIA
Iodometric titration cannot be doine at higher pH (pH > 8) as under alkaline
conditions iodine is converted to hypoiodide, which spontaneously disproportionate into iodide
and iodate: 3 I2 + 6 OH- ? 2 IO3- + 4 I- + 3 H2O It is inadvisable to perform the titration at low
pH as well as protonation of iodide ions occur, which would promote aerial oxidation of iodide
to iodine: 4 HI + O2 ? 2 I2 + 2 H2O H+ ions that present at low pH would also react with the
thiosulfate in the titre: S2O32- + 2 H+ ? SO2 + S + H2O Some reactions involving certain some
reductants are reversible at certain pH, thus the pH of the sample solution should be carefully
adjusted before the performing the analysis. For example, the reaction: H3AsO3 + I2 + H2O ?
H3AsO4 + 2 H+ + 2 I- is reversible at pH < 4. The volatility of iodine is also a source of error
for the titration, this can be effectively prevented by ensuring an excess iodide is present and
cooling the titration mixture. Strong light, nitrite and copper ions catalyzes the conversion of
iodide to iodine, so these should be removed prior to the addition of iodide to the sample. For
prolonged titrations, it is advised to add dry ice to the titration mixture to displace air from the
erlenmeyer flask so as to prevent the aerial oxidation of iodide to iodine.
Solution
Iodometric titration cannot be doine at higher pH (pH > 8) as under alkaline
conditions iodine is converted to hypoiodide, which spontaneously disproportionate into iodide
and iodate: 3 I2 + 6 OH- ? 2 IO3- + 4 I- + 3 H2O It is inadvisable to perform the titration at low
pH as well as protonation of iodide ions occur, which would promote aerial oxidation of iodide
to iodine: 4 HI + O2 ? 2 I2 + 2 H2O H+ ions that present at low pH would also react with the
thiosulfate in the titre: S2O32- + 2 H+ ? SO2 + S + H2O Some reactions involving certain some
reductants are reversible at certain pH, thus the pH of the sample solution should be carefully
adjusted before the performing the analysis. For example, the reaction: H3AsO3 + I2 + H2O ?
H3AsO4 + 2 H+ + 2 I- is reversible at pH < 4. The volatility of iodine is also a source of error
for the titration, this can be effectively prevented by ensuring an excess iodide is present and
cooling the titration mixture. Strong light, nitrite and copper ions catalyzes the conversion of
iodide to iodine, so these should be removed prior to the addition of iodide to the sample. For
prolonged titrations, it is advised to add dry ice to the titration mixture to displace air from the
erlenmeyer flask so as to prevent the aerial oxidation of iodide to iodine..
Presentation slide on iodometric and iodimetric titration for the student seeking a quality slide on the subject. I added the following topics to this slide:
1.CONTENT
2.Titration
3.Types of Titration
4.Redox titration
5.Iodometry
6.Iodimetry
7.Difference between iodometric and iodimetric titration
8.Analytical applications on Iodometric and Iodimetric titration
9.Conclusion
Official compound of iodine and iodine contain preparation. Iodine uses, preparation, assay, storage, their physical, chemical properties and deficiency .
3. Iodimetry is......
Determination of a
substance that is a
reductant (ex:
Na2S203 and Vit C)
with a standard
solution that is an
oxidant (ex: iodine
4. reaction, because in this titration we
used I2 for titrat who has character
oxidator.
Iodimetry can produce (terbatas) some
substance.
Indicator can be used:
1. Amylum 1%
2. CCl4
Iodimetri Titration performed in netral
condition or weak acid in the range up to
a weak base
5. Iodometri consist of 2 is :
A. Iodimetri direct method
Bahan pereduksi langsung dioksidasi dengan
larutan baku Iodium. Contohnya pada
penetapan kadar Asam Askorbat.
B. Iodimetri metode residual ( titrasi balik)
Bahan pereduksi dioksidasi dengan larutan
baku iodium dalam jumlah berlebih, dan
kelebihan iod akan dititrasi dengan larutan
baku natrium tiosulfat. Contohnya pada
penetapan kadar Natrium Bisulfit.
6. The Different with Yodometri
Yodometri Yodimetri
Methode Indirect titration Direct titration
Titrant Na2S2O3 I2
Sample Oksidator Reduktor
Added Indicator Near end point Before titration
Titration environment Acid Netral
7. The advantages :
•Faster Processing
•TA is easily to observation
Disadvantages :
•Easly evaporate
•I2 is volatile
8. pH of Reaction
Titrasi iodimetri dilakukan dalam keadaan netral atau
dalam kisaran asam lemah sampai basa lemah. Pada
pH tinggi (basa kuat) maka iodine dapat mengalami
reaksi disproporsionasi menjadi hipoiodat.
I2 + 2OH- IO3- + I- + H2O
Sedangkan pada keadaan asam kuat maka amilum yang
dipakai sebagai indicator akan terhidrolisis, selain itu
pada keadaan ini iodide (I-) yang dihasilkan dapat
diubah menjadi I2 dengan adanya O2 dari udara
bebas, reaksi ini melibatkan H+ dari asam.
4I- + O2 + 4H+ 2I2 + 2H2O
9. • Oxidation level -1,+1,+3,+5, dan +7
• Weak oxidator
• Can be reacted with all of metal element
and non metal element
• Can be reacted with Hidrogen fomed
Halide acid
• Can formed an Oxy acid with formula
HIO,HIO2,HIO3,HIO4.
10. • The solid, black sparkle bluish
• Volatile gas at room temperature into a blue violet
with a pungent odor
• Easly soluble chloroform, carbon tetrachloride, or
carbon disulfide
• Slightly soluble in water
• properties of metal resembling
• May cause mumps
13. • Add 18 grams of KI
• Dissolve in water
• Weight 12.90 g I2
• Dissolve in water
• Pour KI solution into I2 solution
• Dilute to 1 L
14. • Weighed 1.0000 grams As2O3 +
• Introduced into 100 ml measuring flask
• Added + 10 ml 4N NaOH
• Added 2-3 drops of PP
• Neutralized with 4N H2SO4, until the pink color of
the solution becomes a hint
• Added 3 grams of crystal NaHCO3
• Pipette 10 ml, inserted into erlenmeyer teaser, then
diluted to 100ml +
• Added indicator Kanji 2 -3 drops
• Dititar with I2 solution until it reaches TA Blue light
hint