1. CERIMETRI
SMK Negeri 13 Bandung

2. PRINCIPAL
Based on reduction Ce4+ becomes Ce3+ by reducing agent Reaction of reduction Ce4+: Ce4+ + e  Ce3+

3. The Characteristics and Advantages Ce (IV
In solution there is only in condition of Ce4+ and Ce3+
A real strong oxidant matter in a stong acid situation, potential reduction in H2SO4 1-8 N as big as 1.43 ± 0.05 Volts. If the solution is neutralized, power oxidant declines because of hydrolysis.
Ce (IV) solution very stable for long time in H2SO4 solution. Doesn't require protection from light, and can be boiled with a flash in the pan without changing concentration

4. The Characteristics and Advantages Ce (IV
Can be used in determination of reducer matters in high concentration of HCl.
Ce (IV) 0,1N Solution is not too colourfull so, it is easy to read miniscus
In reaction of Ce ( IV) salt at acid solution with reducer matters, change of its oxidation number is :
Ce4+ + e ⇄ Ce3+, hence BE = Mr

5. The Characteristics and Advantages Ce (IV)
Ce(SO4)2 is multipurpose oxidant, can be used widely. Most all matters which can be titrated by KMnO4 also can be standardized with Ce(IV)
Ce ( IV) can be used for determination of iron in HCl solution without reactant Zimmermann-reinhardt
Ce(SO4)2 Solution is best standardized with arsen oxide. Other matter of which can be applied that is; sodium oksalat, pure iron, potassium ferosianida anhidrous and amonium ferro sulphate.

6. The Characteristics and Advantages Ce (IV
Cerium in chloride acid is very unstable, reaction:
2Ce4+ + 2Cl ⇄ 2Ce3+ + Cl2
so that HCl cannot be used in oxidation with excessive sulphate cerium.
But direct titration with sulphate cerium in dilute medium HCl at room temperature, can be done.

7. Potential of Ce(iv) in Acid 1M
HClO4 : V
HNO3 : V
H2SO4 : V
HCl : V

8. Preparation of Ce(SO4)2 standard solution
From cerium amonium ( IV) nitrate
From cerium ( IV) sulphate
From cerium amonium ( IV) sulphate
From cerium ( IV) hydroxide

9. Filters Ce(OH)4 formed with Sintered-glass
Preparation of Ce(SO4)2 standard solution from cerium amonium ( IV) nitrate
28 g ( NH4)2Ce(NO3)6 pa is dissolved with 100 ml aquadest in chemical glass 600 l
Adds dilute NH4OH (± 60 ml NH4OH 2,5N) slowly, keep stirring until NH4OH excessive
Filters Ce(OH)4 formed with Sintered-glass
Wash precipitate 50 ml aquadest for 5 times, and lets precipitate during 30 minutes on sintered- glass

10. Preparation of Ce(SO4)2 standard solution from cerium ammonium ( IV) nitrate
Removes precipitate into beaker glass, rinses precipitate remaining with 4x50 ml sulphate acid 2M which has been heated beforehand at temperature 600C
Heats precipitate until precipitate dissolve perfectly
Cooling the solution, carries over into volumetric flask 500 ml, makes it to the mark with aquadest, standardization beforehand before applied

11. Dissolves residue yielded in H2SO4 1M.
Preparation of Ce(SO4)2 standard solution from cerium ammonium ( IV) nitrate
Way of 2
55,0 g ( NH4)2Ce(NO3)6 pa is evaporated in evaporation dish until dry approximant with excessive H2SO4 concentrate( 48 ml) .
Dissolves residue yielded in H2SO4 1M.
Removes in volumetric flask 1L, adds sulphate acid 1M until near by border, mark it up with addition aquadest, standardization beforehand before applied. .

12. Ce(SO4)2 Weight out 35-36 g pure Ce(SO4)2 into chemical glass 600 ml.
Preparation of Ce(SO4)2 standard solution from cerium ammonium ( IV) nitrate
Ce(SO4)2
Weight out g pure Ce(SO4)2 into chemical glass 600 ml.
Adds 56 ml H2SO4 1:1, swirled with slow warm-up until incessant salt.
Carries over into volumetric flask 1L is corking glass.
Dilute with aquadest until to the mark.

13. Preparation of Ce(SO4)2 standard solution from cerium ammonium ( IV) nitrate
(NH4)4[Ce(SO4)2].2H2O
Weight out g (NH4)4[Ce(SO4)4]2H2O pure, put into 28 ml H2SO4 solution /500 ml aquadest.
Swirled solid matter until dissolve then carries over into volumetric flask 1L, dilute it into the mark.

14. Preparation of Ce(SO4)2 standard solution from cerium ammonium ( IV) nitrate
Ce(OH)4
Placed 21 g Ce(OH)4 in chemical glass 1.5 l
Adds be swirled by 100 ml H2SO4.
Stirs and adds 300 ml aquadest slowly and carefully.
Hushed one night, if there are residue, filtered it. Filtrate carried over into volumetric flask 1L, dilute until to the mark.

15. Forms of sulphate cerium
Preparation of Ce(SO4)2 standard solution from cerium ammonium ( IV) nitrate
Recrystallization
Eliminates ions
Forms of sulphate cerium

16. Recrystallization
125 grams (NH4)2Ce(NO3)6 technical dissolved in 100 ml HNO3 1:3 and 40 grams NH4NO3
Heats then filters in a state of temperature with sintered- glass.
Made cool the filtrate in ice, filters crystal formed with sintered - glass and continues suction during 1-2 hours that rest of nitrate acid castaway.
Dries crystal at temperature oC.

17. Eliminates ions
Weight out 28 grams dry crystal, dissolve in 100 ml water.
Add 60 ml NH4OH 2,5 N little by little while stirring until precipitate is formed.
Filter precipitate with sintered - glass and cleans with 5 x 50 ml water in order to NH4NO3 castaway.
Continues suction during 30 minutes in order to the rest of water castaway.

18. To form of sulphate cerium
Removes precipitate into chemical glass and rinses sintered - glass with 50 ml Warm H2SO4
4 N ( 60 oC).
Stir while heating in order to make precipitate dissolved, makes cool.
Carries over in volumetric flask 500 ml then mark it up.

19. Standardization Standard Solution Ce ( IV)
With As2O3
With pure iron
With Na2C2O4
With salt Mohr

20. Standardization Standard Solution Ce ( IV) with As2O3
Weight out 0.2 g As2O3 pa, carries over in chemical glass 400 ml or erlenmeyer 350 ml.
Adds 20 ml NaOH 2M, heats slow until dissolving perfectily, makes cool finite of room temperature.
Adds 100 ml aquadest + 25 ml H2SO4 2.5 M + 3 drip osmium tetroksida 0.01 M and 0.5 ml indicator fenilantranilat or 12 drips ferroin.
Titration with Ce(SO4)2 0.1 N until colour changed ( red-orange becomes pale blue)
Do triplo.

21. Standardization Solution. Standard Ce ( IV) with As2o3
Reactions:
As2O3 + 4OH- → 2HAsO32- + H2O
2Ce4+ + HAsO32- + H2O → 2Ce3+ + HAsO H+
At equivalence point, mek Ce4+ = mek HAsO32-
The most precise indicator is ferroin with Eo = 1.06 Volts or fenilantranilat with Eo = 0.89 Volts
Required existence of osmium tertroxide catalyst because the reaction is very slow at room temperature.

22. Standardization Standard Solution Ce ( IV) with Pure Fe
Weight out accurately 0.2 grams of pure iron strand of metal
Put into chemical glass 150 ml
Add 20 ml HCl 1:1 then heat on the steam bath until all irons dissolves
Add Sncl2 drip for the shake of drip until solution do not having colour or becoming green very young then adds 1-2 drips excessive SnCl2

23. Standardization Standard Solution Ce ( IV) with Pure Fe
Made cool under current, then poured 20 mL saturated solution HgCl2 at the same time, lets during 3 minute
Rinses the solution into erlenmeyer flask 500 mL + 2 drip feroin indicator
Titration with Ce(SO4)2 until the colour changed from pink become pale yellows.
Do blanko standarization

24. Standardization Standard Solution Ce ( IV) with Pure Fe
Reactionsi:
2Fe + 6HCl → 2FeCl3 + 3H2
2Fe3+ + Sn2+ → 2Fe2+ + Sn4+
Fe 2+ + Ce4+ → Fe3+ + Ce3+
At equivalence point, mek Ce4+ = mek Fe2+ = mek Fe
The most precise indicator is ferroin with Eo = 1.06 Volt or fenilantranilat with Eo = 0.89 Volt
Sncl2 applied must be fresh, because SnCl2 can be oxidized by air
HgCl2 added to oxidize rest of SnCl2

25. Standardization Standard Solution Ce ( IV) with Na2C2O4
Weight out accurately 0.2 grams Na2C2O4 pa. then puts it into erlenmeyer flask 250 ml.
Adds mL H2SO4 1 M then heats finite of temperature 60 oC then adds 30 mL Ce(IV) which will be standardized, drip for the shake of drip
Re-heats finite 60 0C then added 10 mL Ce(IV) which will be standard, re-heats finite 600C then added 10 mL Ce(IV) which will be standardized and hushed during three minutes.
Made cool and back-titration of excess Ce(IV) with iron ( II) solution with indicator ferroin.

26. Standardization Standard Solution Ce ( IV) with Na2C2O4
Reactions:
C2O Ce4+ → 2CO2 + 2Ce3+
Ce4+ + Fe2+ → Ce3+ + Fe3+
The most precise indicator is ferroin with Eo = 1.06 Volts or fenilantranilat with Eo = 0.89 Volts
Done heat-up because reaction between Na2C2O4 takes place quickly at high temperature.
Applied back-titration procedure because redox indicator will be oxidized at high temperature.

27. Standardization Standard Solution Ce ( IV) with Mohr salt
Way of 1
Weight out accurately 1 gram Mohr salt, dissolves with H2SO4 4 N and rinse into volumetric flask 250 ml with water of O2 free
Pipette 25 ml solution into Erlenmeyer flask, adds to depth 25 mL H2SO4 1 N and 6-8 drips ferroin
Titration with Ce(IV) solution until colour changed from red to green

28. Standardization Standard Solution Ce ( IV) with Mohr salt
Way of 2
Pipette 25 mL Ce ( IV) solution then acidified and adds ferroin
Titration with standard solution of finite Mohr salt until colour changed from green becomes red

29. Standardization Standard Solution Ce ( IV) with Mohr salt
Reactions:
Fe 2+ + Ce4+ → Fe3+ + Ce3+
At equivalence point, mek Ce4+ = mek Fe2+
The most precise indicator is ferroin with Eo = 1.06 Volts or fenilantranilat with Eo = 0.89 Volts
Mohr Salt dissolved in free water of O2 to prevent oxidation of Mohr salt by O2 in water.

30. What is going on at the time of end point?
Indicator turns colour because indicator experiences oxidation ( if Ce4+ in burette) or reduction ( if done titration indirectly / back-titration).
oxidation of Indicator happened if Fe2+ has used up/finished reacts and potential solution has reached potential reduction indicator value

31. Determination of (NO2-)
Weight out accurately 2 ml sample solution of nitrite then dilutes in volumetric flask 250 ml with free water of O2.
Removes 50 ml standard solution Ce ( IV) into Erlenmeyer flask, acidifies with H2SO4 4 N.
Pipette 25 mL of nitrite solution sample and adds into Ce ( IV) solution in Erlenmeyer flask carefully with pipette tip as near by possible with surface of Ce ( IV) solution.

32. Determination of (NO2-)
Lets during 5 minutes.
Adds 6-8 indicator drips ferroin.
Titration with standard solution ferro until colour changed from green to become red.

33. Determination of (NO2-)
Reactions
NO2- + 2Ce4+ + H2O → NO3- + 2Ce3+ + 2H+
excess
Ce4+ + Fe2+ → Ce3+ + Fe3+
mek Fe2+ = mek Ce4+ excess
mek Ce4+ excess = mek Ce4+ - mek NO2-
mek Fe2+ = mek Ce4+ - mek NO2-
mek NO2- = mek Ce4+ - mek Fe2+

34. Determination of (NO2-)
Nitrite easy to be oxidized by O2, therefore water applied as nitrite sample solvent must free of O2 and position of when adding nitrite sample must as near by possibly, to obviate contact with air.
It is not done direct titration because nitrite easy to be oxidized by air and can react with air during shaking process.
The most precise indicator is ferroin with Eo = 1.06 Volts or fenilantranilat with Eo = 0.89 Volts
Colour changed when end point, green become red