Mindmap
Redox Titrations
Inhalt der Mindmap
Redox Titrations
Definitions
- Oxidation
- Reduction
- Oxidant
- Reductant
- Potential (E)
- ↑E° >> strong oxidant
- ↓E° >> strong reducing
- To complete redox reaction >> differance in E° between 2 systems > 0.2 V
- Measure !
- Electrochemical cell
- Nernest eq.
- Effect of common ion
- Zimmermann's reagent
- MnSO4
- H3PO4
- H2SO4
- Zimmermann's reagent
- Effect of pH
- Ox. contain O
- Ox contain no O
- Effect of complexing agent
- Det. of Zn+2
- Effect of ppt agent
- Effect of common ion
- substance act as ox or red
- ability to gain or loss e-
- potential of other system
- Eq. weight
- Oxidation no.
- How to balance ?
Detection of E.P.
- Potentiometrically
- Redox titration curve
- Factors
- no. of e- transfer
- Symmetrical
- Unsymmetrical
- Potential differance
- ↑ >> complete
- no. of e- transfer
- Factors
- Indicator method
- specific
- starch
- Blue with I2
- SCN-
- Red with Fe+3
- starch
- Self (colored titrant )
- KMnO4
- I2
- Brown in aq.
- violet in organic
- K2Cr2O7 can't be used
- Irreversible
- destroyed by strong ox
- ex.
- M.R.
- M.O.
- External
- outside reaction medium
- Diphenylcarbazide
- det. of Fe+2 # st. Cr2O7-2
- E.P. diphenylcarbazone >> violet
- Redox
- Requirements
- Highly colored + conjugated system
- Ex.
- Ferroin
- Det. of Fe+2 # Ce+4
- Ferroin >> Ferrin
- E.P. Pale blue
- DPA
- Det. of Fe+2 # st. Cr2O7-2
- in presence of H3PO4
- water insol
- so, add H2SO4
- DPA sulphonate
- water sol
- DPA sulphonate
- so, add H2SO4
- E.P. colorless > violet
- Det. of Fe+2 # st. Cr2O7-2
- Methylene blue
- E.P. colorless >> blue
- Ferroin
- transition range
- specific
Oxidizing agents
- KMnO4
- adv
- self
- strong
- low cost
- disadv
- oxidize Cl-
- UseZimmerman's !
- pH dependent
- strong acidic
- MnO4- → Mn+2
- Fe+2
- C2O7-2
- AsO3-3
- MnO4- → Mn+2
- strong alkaline
- MnO4- → MnO4-2
- add BaCl
- BaMnO4 ↓
- Filter
- BaMnO4 ↓
- add BaCl
- MnO4- → MnO4-2
- weak alkaline
- MnO4-→ MnO2 ↓
- strong acidic
- oxidize Cl-
- standardization
- st. oxalix a
- Reactions
- strong acidic medium
- Direct
- Reducing agents
- Fe+2
- add zimmernann's
- Fe+2
- Pharmaceutical compounds
- H2O2
- act as Red
- reduce MnO4-
- act as ox
- oxidize I-
- act as Red
- H2O2
- Reducing agents
- Indirect
- cations form insol oxalate
- ex. Ca+2
- cations form insol oxalate
- Direct
- strong alkaline medium
- Back titration
- C → CO3-2
- ex. glycerol
- ex. mixture of CH3COOH + HCOOH
- acid-base >> total
- Redox >> HCOOH
- C → CO3-2
- Back titration
- weak alkaline medium
- C → CO3-2 + C2O4-2
- ex. glycerol
- C → CO3-2 + C2O4-2
- strong acidic medium
- adv
- Iodine
- disadv
- weak
- limited solubility
- limited app
- volatile
- preparation
- I2 + I- → I3-
- IO3- + I- → I2
- standardization
- S2O3--
- neutral medium
- S2O3--
- Detectio of E.P.
- self
- specific (starch)
- can't be used in acidic medium
- Organic solvent
- Reactions
- Direct ( Iodimetry )
- reducing agents
- S2O3--
- Sn++
- AsO3-3
- Pharmaceutical compounds
- Dimercaprol ( BAL)
- Novalgine
- water content
- ex.
- amoxicillin trihydrate
- 11.5 -14.5 %
- Amiloride HCl
- 11 - 13 %
- amoxicillin trihydrate
- Karl-Fisher reagent
- I2
- SO2
- Pyridine
- detected potentiometrically
- Pt. working electrode
- calomel reference electrode
- ex.
- reducing agents
- Indirect (Iodometry )
- AsO4-3
- CuSO4
- add NH4SCN
- In alkaline medium
- Det. of Glucose
- Direct ( Iodimetry )
- disadv
- KIO3
- half eq acc to pH
- prepared as molar sol
- standardization
- Iodometrically
- uses
- source of I2
- Andrew's method
- det. of mix ( I2 & I- )
- strong acidic medium
- Ind : CHCl3 or irreversible
- Lange's method
- dil. HCL + KCN
- Ind : starch
- det. of mix ( I2 & I- )
- BrO3-
- 1ry st
- irreversible ind
- uses
- source of Br2
- back titration
- Phenol
- Isoniazide (INH)
- NBS
- strong
- HCl
- BrCl
- determination
- ascorbic acid
- irreversible ind
- sulphonamide
- irreversible ind
- Phenothiazine
- E.P. potentiometrically
- ascorbic acid
- KMnO4
Oxygen flask method
- organic sulphur compounds
- ignition : S → SO2 or SO3
- absorbing liq : H2O2
- SO4--
- # BaCl2
- ind: sod. rhodizonate
- E.P. : Ba rhodizonate (red ppt)
- organic phosopho compounds
- ignition : P → PO4-3
- absorbing liq : dil HNO3
- + amm. molybdate
- canary yellow
- spectrophotometry
- canary yellow
- Risedronate
- organic halide compounds
- Cl-
- Ignition : Cl- → Cl2
- absorbing lliq : NaOH contain some H2O2
- determination : Arginometry
- Mohr's
- ind : K2Cr2O7
- E.P. reddish broen ppt
- Mohr's
- cloxacillin
- Br-
- # Hg++
- [Fe(SCN)6]-3 ind
- E.P : disappearance of red color
- # Hg++
- Cl-
- organic sulphur compounds
Pre-oxidant and pre-reductant
- adjust oxidation state
- requirements
- not interfere
- easily removed
- Pre oxidant
- gaseous
- ozone
- in acidic medium
- Mn++
- Ce+3
- in alkaline medium
- NO2-
- I-
- removed by boiling
- in acidic medium
- bromine
- specific for I-
- removed by addition of phenol
- ozone
- Homogenous
- amm persulphate
- Ce +3
- Fe+2
- Mn+2
- removed by boiling
- H2O2
- In acidic medium
- Sn+2
- Fe+2
- removed by boiling
- In acidic medium
- HClO4
- hot + conc
- Fe+2
- S, As , Sb
- removed bt dilution or cooling
- amm persulphate
- solid
- sod bismuthate
- Mn+2
- Cr+3
- removed by filtration
- sod bismuthate
- gaseous
- Pre reductant
- gaseous
- H2S
- Fe+3
- removal by boiling
- H2S
- Homogenous
- SnCl2
- As+5
- Fe+3
- removal by addition of HdCl2
- SnCl2
- Metalic
- Jones reductor
- Zn + HgCl2
- zn amalgum
- non selective
- uses
- Fe+3
- Ti+4
- MnO4-
- Cr2O7--
- disadv
- NO3-
- O2
- Zn + HgCl2
- Walden's reductor
- less powerful more selective
- Ag + HCl
- uses same jones
- disadv
- agcl ↓
- dil NH3
- Ag(NH3)+
- sol
- Ag(NH3)+
- dil NH3
- air
- agcl ↓
- Jones reductor
- gaseous
Informationen
- Beschreibung
- Mindmap am Redox Titrations, erstellt von سمية علي am 28/12/2014.
- Erstellt von
- سمية علي
- Aufrufe
- 10
- Bewertung
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