Titrimetri  melibatkan rekasi oksidasi dan reduksi yg berkaitan dg perpindahan elektron

  T I T RA SI REDOK S o k s i d a s i d a n

  T i t r i m e t r i  m el i bat k an r ek asi 

r e d u k s i y g b e r k a i t a n d g p e r p i n d a h a n e l e k t r o n

Pe r u b a h a n e - p e r u b a h a n v a l e n s i at o m / i o n ya n g b e r s a n g k u t a n . ya n g b e r s a n g k u t a n .

• Z at p e n g o k s i d m e n d a p at k a n e d a n t e r e d u k s i

  at o m / i o n m e n u r u n  v a l e n s i  Z at p e r e d u k s i k e h i l a n g a n e - d a n t e r o k s i d a s i

  Va l e n s i at o m /i o n m e n i n g k at  

  Co n t o h : Pe r u b a h a n d a r i :

  2 + 3 + +2  +3 

  Fe   Fe

• Cl

  r e a k s i o k s i d a s i   Cl

  2

• 1  0  2 + 0  +2 

  Cu  Cu  Pr i n s i p r e a k s i r e d o k s (Re d u k s i – Ok s i d a s i ) Pr i n s i p r e a k s i r e d o k s (Re d u k s i – Ok s i d a s i )

  Ox + Re d + Ok

  Re d

  1

  2

  1

  2 ½ reaksi syst reduksi ½ reaksi syst oksidasi Tereduksi teroksidasi

  Pr o s e s o k s i d a s i – r e d u k s i t e r j a d i b e r s a m a s a m a Se c a r a u m u m r e a k s i r e d o k s d i g a m b a r k a n

• a + (a -n )+ o

  M + n e : E V ½ r e a k s i t e r e d u k s i  M  Ox . Re d . d i k at o d a

  1

  1 a + (a -n )+ -

  M + n e : E V ½ r e a k s i t e r o k s i d a s i   M Re d . Ox . d i a n o d a

  2

  2 Co n t o h : Co n t o h : 2 + 4 + 3 + 3 +

  Fe + Ce + Ce  Fe 

• 2 + 3 +

  o

  Fe + e : E = 0 ,7 7 1 Vo l t

    Fe

  p o t e n s i a l r e d u k s i 4 + 3 + o

  Ce : E = 1 ,6 1 Vo l t

• e -  Ce 

Z at p e n g o k s i d l e m a h  c ender ung k ur ang

s h g h a n ya d p t m e n g o k s i d a i zat p e r e d u k s i y g

• p l g s i a p m e n g h a s i l k a n e

  

K e k u at a n zat p e n g o k s i d a s i d a n p e r e d u k s i d i

t u n j u k k a n o l e n i l a i p o t e n s i a l r e d u k s i n ya .

  POT EN SI A L STA N DA R _o SETENGAH REAKSI Sistem Redoks E Volt

• _{- +}
₂ H O + 2H + 2e O 1,77 _{2 2 + - -}  2 H

  MnO + 4H + 3e + 2H O 1,695 _{4 4+ e- 3+}  MnO

₂

₂
• + Ce

  1,6 1  Ce _{2+ + - -}

  MnO + 8H + 5e + 4 H O 1,51 ₄  Mn _{3+ + 2- - 2} 1,3 3 Cr O + 14 H + 6e + 7H O _{2 7 - + + - 2+ 2+}  2Cr ₂ MnO MnO + 4H + 4H 2e 2e + 2H + 2H O O 1,23 1,23 _{2 2 + - -}  Mn  Mn _{2 2}

  2IO + 12H + 10e O 1,20 _{3 - -}  I2 + 6H ₂ H O + 2e 0,88 _{2 2}  2OH _{- - 2+}

  Cu + I + e 0,86 _{3+ 2+ -}  CuI

  0,771 Fe + e  Fe _{- + -}

  O + 2H + 2e O 0,682 ₂  H _{2 2} I (aq) + e- 0,6197 _{2 - +}  2I

  H AsO + 2H + 2e + 2H O 0,559 _{3 4}  HAsO _{2 2}

  SETENGAH REAKSI Sistem Redoks E ^o Volt

  I ^3- + 2e ^-  3I ^-

  0,5355 Sn ⁴⁺ + 2e ^-  Sn ²⁺

  0.154 S ₄ O ₆ ^2- + 2e ^-  S ₂ O ₃

^2-

0,08

  2H

• ⁺ + 2e ^-

   H ₂ 0,0000 ** Zn ²⁺ + 2e ^-

• -0,763

   Zn

  2H ₂ O + 2e ^-  H ₂

  2H ₂ O + 2e ^-  H ₂

• + 2OH
• ^- -0,828
• + 2OH
• ^- -0,828
• Normal Hidrogen Elektrode (

  NHE ) atau Standard Hydrogen Elektrode (

  SH

  E) Re a g e n ya n g b e r p e r a n s e b a g a i Re d u k t o r /Ok s i d at o r a u t o o k s i d a s i .   Re a g e n m e n g a l a m i T i t r a s i r e d o k s m e r u p a k a n b a g i a n d r T i t r a s i Vo l u m e t r i ya n g a k a n t e r l a k s a n a d e n g a n b a i k b i l a :

• K e s e t i m b a n g a n r e d o k s t e r c a p a i d e n g a n c e p at s e t i a p p e n a m b a h a n vo l u m e t i t r a n
• A d a n ya i n d i k at o r p e n u n j u k T E. s t o k h i o m e t r i
• ½ r e a k s i s y s t o k s i d a s i d a n ½ r e a k s i s y s t r e d u k s i s a at t i t r a s i s e l a l u t e r j a d i k e s e t i m b a n g a n p a d a s e l u r u h t i t i k p e n g a m at a n

  

Pe n g a r u h K o n s e n t r a s i & Re a k s i d a r i m e d i u m

  H u b u n g a n a n t a r a b e d a p o t e n s i a l ( E ) s i s t i m r e d o k s d a n k o n s e n t r a s i b e n t u k t e r o k s i d a s i d a n t e r e d u k s i d i t u n j u k k a n o l e h p e r s N ERN ST s b g t u r u n a n d a r i H K .Te r m o d i n a m i k a .

  RT RT [ s p e s i e s t e r e d u k s i ] [ s p e s i e s t e r e d u k s i ] o

  E = E - ------- -------------------------------- l n (1 ) n F [ s p e s i e s t e r o k s i d a s i ]

  o

  E = p o t e n s i a l s t a n d a r d l n = 2 ,3 0 3 l o g R = k o n s t a n t e g a s (8 ,3 1 3 j o u l e ) T = t e m p e r at u r a b s o l u t F = k o n s t a n t e Fa r a d a y (9 6 5 0 0 c o u l o m b )

  Pe n e n t u a n TAT at a u T E .

  K u r ve T i t r a s i Re d o k s Da l a m t i t r a s i r e d o k s zat at a u i o n ya n g t e r l i b at d l m r e a k s i b e r u b a h s e c a r a k o n t i n y u , ya n g a k a n m e m p e n g a r u h i p e r u b a h a n p o t e n s i a l (E) l a r u t a n .

  De n g a n m e n g a l u r k a n p o t e n s i a l De n g a n m e n g a l u r k a n p o t e n s i a l (E) (E) t h d p e r u b a h a n t h d p e r u b a h a n

  Vo l t i t r a n

  y g d i t a m b a h k a n  di per ol eh k ur ve t i t r as i  s p t k u r ve t i t r a s i n e t r a l i s a s i .

  

2 +

  Co n t o h : t i t r a s i g a r a m Fe d g K M n O d a l a m l a r u t a n

  4

  a s a m

  t e r o k s i d a s i

• 2 +
• 2 + 3 +

  M n O + 5 Fe + 8 H M n + Fe + 4 H O

  4

  2

  Re a k s i y g t e r j a d i r eve r s i b e l

  s e l a l u

  ,  l ar ut an ak an  m e n g a n d u n g k e d u a i o n a w a l d a n i o n ya n g t e r b e n t u k s e l a m a r e a k s i , d g k at a l a i n p a d a t i a p t a h a p a n t i t r a s i

  2 + 3 +

  l a r u t a n a k a n m e n g a n d u n g d u a r e d o k s Fe /Fe d a n

• 2 +

  M n O /M n E m e n g g u n a k a n

  4   u n t u k m e n g h i t u n g p e r s 2 at a u 3

  2 + 0 ,0 5 9 1 [ Fe ]

  Pe r s (2 ) E = 0 ,7 7 1 – ----------- l o g -----------

  3 + 3 + 1 [ Fe 1 [ Fe ] ]

  2 + 0 ,0 5 9 1 [ M n ]

  Pe r s (3 ) E = 1 ,5 1 - -------------- l o g -----------------------

  8 n [ M n O ] [ H ]

  4 RT

• ----- x 2 ,3 0 3 = 0 ,0 5 9 1 p e r s (2 ) & p e r s (3 ) m e m b e r i k a n

  

Kurva Titrasi

Consider the titration of iron(II) with • standard cerium(IV), monitored potentiometrically with Pt and calomel electrodes

  . E Vo l t Daerah setelah TE Daerah Sebelum TE

  X TE K U RV E T I T RA SI There are three distinct regions in the titration of iron(II) with standard cerium(IV), monitored potentiometrically with Pt and calomel electrodes .

  1. Before the equivalence point, where the potential at Pt is dominated by the analyte redox pair.

  2. At the equivalence point, where

  m L t i t r a n

  Daerah Sebelum TE Daerah TE There are three distinct regions in the titration of iron(II) with standard cerium(IV), monitored potentiometrically with Pt and calomel electrodes .

  2. At the equivalence point, where the potential at the indicator electrode is the average of their conditional potential.

  3. After the equivalence point, where the potential was determined by the titratant redox pair. Pe r s (1 ) d a n (2 ) d a p at d i g u n a k a n u n t u k p e r h i t u n g a n s e l a n j u t n ya .

  Pe r s (1 ) a k a n l e b i h m u d a h u n t u k m e n g h i t u n g E b e s i k e t i k a p e n a m b a h a n vo l t i t r a n m e n d e k at i T E.

  Se d a n g p e r s (2 ) d i p a k a i u n t u k m e n g h i t u n g E M n O

  4 k e t i k a t e r j a d i k e l e b i h a n vo l t i t r a n .

  Co n t o h : Co n t o h :

  50 mL lrtn 50 mL lrtn KMnO KMnO _{4 4} N N _{x x} 100 mL _{2 + 3 +} FeSO ₄ Di c a p a i 5 0 % Fe  Fe N _x

  B r p E p a d a k e a d a a n s e b e l u m T E , T E , d a n s e s u d a h T E

  M a k a d a p at d i t u l i s k a n 0 ,0 5 9 1 [ 5 0 ]

  E = 0 ,7 7 1 - ---------- l o g ------- = 0 ,7 7 1 vo l t .

  1 [ 5 0 ] K e a d a a n s e b e l u m T E.

  E p a d a p e n a m b a h a n 0 ,1 s e b e l u m T E  pada pe (+)  9 9 ,9 m L l r t K M n O 9 9 ,9 m L l r t K M n O  

  4

  0 ,0 5 9 1 [ 0 ,1 ]

  E = 0 ,7 7 1 - ----------- l o g ---------- = 0 ,9 4 4 vo l t

  1 [ 9 9 ,9 ] K e a d a a n s e s u d a h T E 0 ,0 5 9 1 ‘ [ 1 0 0 ]

  E = 1 ,5 1 - ------------ l o g ----------------- = 1 ,4 7 5 vo l t

• K e a d a a n T E , d i a s u m s i k a n [ H ] = 1 M ,  

  

2 +

  0 ,0 5 9 1 [ Fe ] E = 0 ,7 7 1 - ------------ l o g ----------- ½ s e l s i s t r e d o k s

  

3 +

  1 [ Fe ]

  

2 +

  0 ,0 5 9 1 [ M n ] E = 1 ,5 1 - ------------ l o g ------------- ½ s e l s i s t r e d o k s

  5 [ M n O 5 [ M n O ] ]

  

4

  

4

• [ +]

  2 + 2 +

  0 ,0 5 9 1 [ Fe ] [ M n ]

  6 E = 0 ,7 7 1 + 5 x 1 ,5 1 - ---------- l o g ------------------------ (* * * * )

  3 + -

  1 [ Fe ] [ M n O ]

  4 Pa d a T E b a n ya k n ya e q t i t r a n = e q t i t r at .

• -

  Pa d a T E b a n ya k i o n M n O ya n g d i (+) k a n s e s u a i d g

  4

  p e r s a m a a n r e a k a s i b e r i k u t :

• 2 + -

  2 + 3 +

  M n O + 5 Fe + 8 H M n + 5 Fe + 4 H O

  4

  2

• Pa d a k e s e t i m b a n g a n s e t i a p 1 i o n M n O h a r u s a d a

  4 2 + 5 i o n Fe Sh g Sh g p e r s a m a a n p e r s a m a a n (* * * * ) (* * * * ) l o g [ ] l o g [ ] = =

   h a r g a  h a r g a 0 ,7 7 1 + (5 x 1 ,5 1 ) M a k a E = ------------------------------ = 1 ,3 8 7 vo l t

  T E

  6 Se c a r a u m u m j i k a E

  o

  zat p e n g o k s i d d a n p e r e d u k s i d i n yat a k a n s e b a g a i E

  o

  1

  d a n E

  o

  2

  d a n k o e f i s i e n s t o k h i - o m e t r i s e b a g a i a d a n b ,  E l ar ut an s aat TE adal ah: 1 ). B u at k u r ve t i t r a s i c o n t o h d i at a s d g m e m p e r h at i k a n k e a d a a n s e b e l u m T E, T E, d a n k e l e b i h a n t i t r a n ( s e s u d a h T E d i c a p a i ).

   b .E

  o

• a .E

  1

  o

  2 E. T E

  = ------------------------- (4 ) a + b 2 ). B u k t i k a n s e c a r a m at e m at i k a d g m e n g a c u r e a k s i s t o k h i o m e t r i r u m u s d i at a s K u r ve t i t r a s i r e d o k s s e c a r a u m u m s a m a d g k u r ve T i t r a s i n e t r a l i s a s i (a s a m -b a s a ).

  E b e r u b a h t i b a -t i b a s a at T E, d a n b e r i k u t n ya k u r ve t e t a p m e n d at a r  i ni m enunj uk k an per ubahan E  s a n g at l a m b at s e l a m a t i t r a s i . b e l o k a n p d k u r ve d a p at d i g u n a k a n u t k p e n e n t u T E d g b a n t u a n i n d i k at o r.

  o

  B e s a r n ya p e r u b a h a n E l r t t g t p a d a p e r b e d a a n E d a r i k e d u a s i s t i m r e d o k s .

  K u r v a o k s i d i m e t r i b i a s a n ya t d k t g t p e n g e n c e r a n , k r n Pe r s N ERN ST m e r u p a k a n p e r b a n d i n g a n [ t e r o k s i d a s i ] [ t e r e d u k s i ] , s h g t d k b e r u b a h d g p e n g e n c e r a n . T i t i k b e l o k k u r ve t i t r a s i r e d o k s d a p at d i p e r l e b a r j i k a Sa l a h s at u i o n ya n g t e r b e n t u k m e m b e n t u k k o m p l e k s .

• 3 -

  Co n t o h : p a d a t i t r a s i r e d o k s p e n a m b a h a n PO , F

  4 3 +

    b e r g a b u n g d g Fe   k o m p l e k s s t a b i l

  = = [ Fe (PO ) ] , [ Fe F ]

  4

  2

  6

  

I n d i k at o r Re a k s i Re d o k s .

  T E t i t r a s i r e d o k s d a p at d i l a k u k a n d e n g a n / t a n p a I n d Ta n p a i n d i k at o r b i s a d i l a k u k a n j i k a s e m u a zat p e r e d u k s i t e r o k s i d a s i o l e h o k s i d at o r d a n m e m b e r i k a n p e r u b a h a n f i s i k (w a r n a /t i d a k b e r w a r n a ) ya n g b i s a t e r a m at i d g j e l a s .

  Co n t o h : M n O d l m s u a s a n a H , w a r n a u n g u l e m b a

  4

  4

• 2 + 2 +

  y u n g i o n M n O y u n g i o n M n O M n M n k e t i k a k e t i k a

  4 h i l a n g k r n t e r e d u k s i  h i l a n g k r n t e r e d u k s i 

  Se m u a zat p e r e d u k s i t e l a h d i t i t r a s i , k e l e b i h a n 0 ,1 m L p e r m a n g a n at  l ar ut an m enj adi m er ah m uda.

   Co n t o h l a i n : t i t r a s i zat p e r e d u k s i d g l r t I o d , p e r u b h n

• , w a r n a c o k l at g e l a p  t ak ber w ar na dr I od I 

  2   I

  k a r e n a w a r n a I o d k r g t a j a m m k u t k m e m p e r t a j a m <<) d i g u n a k a n i n d i k at o r a m i l u m  bi r u k uat (I

  

  2

  I n d i k at o r  ber ubah w ar na k et i k a E l r t n y g di t i t r as i  m e n c a p a i h a r g a t e r t e n t u .

  I n d + n e I n d

  o k s r e d

  De n g a n m e n e r a p k a n p e r s N e r n s t  da pat di t ul i s k an 

  0 ,0 5 9 1 [ I n d ] r e d o o

  E = E E = E - ---------- l o g ---------------- - ---------- l o g ---------------- (5 ) (5 ) i n d i n d n [ I n d ] o k s

  U t k k e p e n t i n g a n p r a k t e k r e n t a n g j a n g k a u a n i n d i k at o r Re d o k s d i n yat a k a n d e n g a n :

  0 ,0 5 9 1 o

  E = E - -------------- (6 ) i n d

  Co n t o h :

  o

  I n d i k at o r Di f e n i l a m i n E = +0 ,7 6 vo l t , n = 2  

  Re n t a n g E I n d i k at o r r e d o k s : 0 ,0 5 9 1 E = 0 ,7 6 – ----------- = 0 ,7 3 vo l t . Re n t a n g E

  1

  2

  0 ,7 3  0,79 vol t 

  0 ,0 5 9 1 E E = 0 ,7 6 + ------------ = 0 ,7 9 vo l t . = 0 ,7 6 + ------------ = 0 ,7 9 vo l t .

  2

  2

  2 E=0 ,7 3 < < E=0 ,7 9 B e n t u k b e r u b a h b e n t u k t e r e d u k s i b e r t a h a p t e r o k s i d a s i t i d a k b e r w a r n a u n g u l e m b a y u n g

  Indikator Warna teroks Warna teredk Eo.volt Kondisi lrtn Kompl,Fe(II) 5-nitro-1,10 -fenantrolin Biru pucat Merah ungu +1,25

  1M H ₂ SO ₄ Asam 2,3-difenilamin dikarbosilat Biru-violet Tak berwarna +1,12 7-10 M H ₂ SO ₄ Kompl,Fe(II) 1,10-fenantrolin Biru pucat merah +1,11

  1M H ₂ SO ₄ Erioglaucin A Biru-merah Kuning-hijau +0,98 0,5M H ₂ SO ₄ As difenilamin sulfonat Merah-ungu Tak berwarna +0,85 Asam encer E. I n d Re d o k s d g p e r u b w a r n a / k o n d i s i l a r u t a n

  

As difenilamin sulfonat Merah-ungu Tak berwarna +0,85 Asam encer

difenilamin ungu Tak berwarna +0,76 Asam encer P-ethoksikrisoidin kuning merah 0,76

  1M asam Biru metilen biru Tak berwarna +0,53

  1M asam Indigo terasulfonat fenasafranin

  Biru biru Tak berwarna Tak berwarna

• 0,36
• 0,28

  1M asam

  1M asam Re a k s i s a m p i n g d a l a m T i t r a s i Re d o k s

  Sa l a h s at u k e s u k a r a n d a l a m t i t r a s i Re d o k s a d a l a h t e r j a d i n ya r e a k s i s a m p i n g ,s e h i n g g a a k a n m e m p e n g a r u h i p e n g g u n a a n t i t r a n  anl i s a m enj adi t i dak

   a k u r at .

  Co n t o h : p a d a p e n e t a p a n Fe r r o d g p e r m a n g a n at .

• 2 + 2 +
• 3 + 3 + 2 + +

• - 2 +

  5 Fe

  5 Fe + M n O + M n O + 8 H + 8 H

  5 Fe + M n + M n + 4 H + 4 H O O

  5 Fe

  4

  2 Da r i p e r s a m a a n r e a k s i i o n H + d i b u t u h k a n  har us

   d i l a k u k a n d a l a m s u a s a n a a s a m .

• N a m u n s i f at d a r i a s a m ya n g m e n g h a s i l k a n H s a n g at b e r a r t i . Da l a m p r a k t e k a s a m ya n g t e p at d a n b e n a r d i g u n a k a n
Re a k s i ya n g t e r j a d i d g a d a n ya H Cl
• 2 + - -

  1 0 Cl + 2 M n O + 1 6 H

  2 M n + 8 H O + 5 Cl

  4

  2

  2 Te r l i h at k e b u t u h a n p e r m a n g a n at m e n j a d i l b h b a n ya k k a r e n a d i b u t u h k a n u n t u k r e a k s i s a m p i n g .

  k l o r ya n g t e r b e n t u k d a l a m r e a k s i h a r u s m e n g o k s i d a s i

  2 +

  Fe m e n g i k u t i r e a k s i  

  2 + 3 + 3 + - - 2 +

  2 Fe + Cl + Cl

  2 Fe

  2 Fe + 2 Cl + 2 Cl

  2 Fe

2 J i k a s e m u a k l o r a d a d i l a r u t a n , b a n ya k n a y b e s i ya n g

  t e r o k s i d a s i e k i v a l e n d e n g a n b a n ya k n ya p e r m a n g a n at y g d i p e r l u k a n d l m p e m b e n t u k a n r e a k s i s a m p i n g Cl .

  2 N a m u n d a l a m p r a k t e k b e b e r a p a k l o r m e n g u a p d a n i n i

  M e n g a k i b at k a n p e n g g u n a a n p e r m a n g a n at m e n j a d i l b h

  B e b e r a p a s i s t i m r e d o k s CERI M ET RI L r t s t a n d : Ce (I V ) Su l f at (o k s i d at o r ) d p t d i g u n a k a n s p t l r t s t d K M n O

  4 d g s i s t e m T i t r a s i K e m b a l i d g l r t n s t a n d s t a n d N a .Ok s a l at N a .Ok s a l at

  4 + 3 + Ce Ce Ce Ce   k u n i n g t d k b e r w a r n a p e r l u i n d i k at o r   k r g t e r d u k u n g

  (N H ) Ce (N O ) / H Cl O

  4

  2

  3

  6

4 A m o n i u m H e k s a N i t r o Se r at d l m H Cl O

  4 I n d i k at o r : α Pe n a n t r o l i n e , Fe r o i n . Da l a m t i t r a s i d i b u t u h k a n s e n ya w a o r g a n i k u t k m e n g o k s i d a s i d g m e m b e n t u k CO

  2 1 ) 1 2 M H 2 SO4

  H O O

  4 +

  C—CH —CH —C + 1 0 Ce + 1 2 .H O

  2 O OH OH OH 2 ) 4 M H Cl O4

  A s a m t a r t r a t 1 ) n =1 0 , 2 ) n = 6 3 + +

  (1 ) 4 CO + 1 0 Ce + 1 0 H O

  2

  2

  3

  3 O

3 +

  (2 ) 2 CO + 2 H C + 6 Ce + 6 H O

  2

  2 OH Co n t o h a p l i k a s i t i t r a s i Ce r i m e t r i . _{2 +}

  Fe & s u a s a n a a s a m 2 5 0 m L _{4 +} T i

  d i l a r u t k a n s c r p a s t i

  Wo = 1 ,7 5 g r

  t i t r a s i

  Per Titran Ce

  50 mL 0,075 N aliquot

  a ) m e t o d a Wa l d e n Re d u k t o r (A g r e d u k t o r )  m e m b u t u h k a n t i t r a n 1 8 ,2 m L  b ) m e t o d a J o h n Re d u k t o r (Z n r e d u k t o r )   m e m b u t u h k a n t i t r a n 4 6 ,2 m L

  B e r a p a % Fe s b g Fe O d a n % T i s b g T i O

  2

  3

  2 Re a k s i ya n g t e r j a d i p a d a Wa l d e r Re d u k t o r.

  Wa l d e n Re d u k t o r A g

• Ce A g Cl e

  (s ) (s )

• 3 + 2 +
• Fe e Fe

  2 +

  T i O Re a k s i ya n g t e r j a d i p a d a J o h n Re d u k t o r Re a k s i ya n g t e r j a d i p a d a J o h n Re d u k t o r

  2 + -

• J o h n Re d u k t o r Z n Z n 2 e

  (s )

• 2 + 3 +

  Fe e Fe +

• 2 +
• 3 +
• T i O + 2 H O e T i + 3 H O

  3

  2 Pe n ye l e s a i a n s o a l :

  3 + 2 +

  Fe n =1 Da r i Wa l d e n R  Fe 

  T i m e q Fe O s e t a r a m e q t i t r a n Ce r r i

  2

  3

  m e q Ce = 1 8 ,2 x 0 ,0 7 5 W Fe O

  2 3 (m g )

• = m e q Fe O

  2

  

3

M r Fe O / n

  2

3 WFe O = 0 ,0 7 5 x 1 8 ,2 x 1 0 0 = 1 3 6 .5 m g p e r 5 0 m L

  2

3 W Fe O d a l a m s a m p e l = 1 3 6 ,5 x 2 5 0 /5 0 = 6 8 2 ,5 m g

  2

  3 = 3 9 % Da r i J o h n Re d Fe d a n T i t e r e d u k s i

  3 + 2 + 3 + 4 +

  Fe Fe m e q t i t r a n = s e t a r a m e q Fe + T i

  4 + 3 +

  T i T i W.T i O

  2 (m g )

  4 6 ,2 x 0 ,0 7 5 = ------------------- + m e q Fe O

  2

  3 M r.T i O / n

2 W.T i O (m g )

  2

  3 ,4 6 5 m g = -------------- + 1 ,3 6 5 m g 3 5 /1 W.T i O (m g ) = (3 ,4 6 5 – 1 ,3 6 5 ) x 3 5 = 7 3 ,5 m g ‘ / 5 0 m L

  2

  d l m s a m p e l = 7 3 ,5 x 5 = 3 6 7 ,5 m g =3 6 7 ,5 / 1 7 5 0 x 1 0 0 %

  PEM A N GA N OM ET RI

  M e t o d a t i t r i m e t r i d g l a r u t a n s t a n d a r d K M n O

  4 T i t r a n K M n O4  ok s i dat or k uat

  (+) * s b g s e l f i n d i k at o r t i t r a n

• T E d i t u n j u k k a n o l e h p e r u b a h a n w a r n a n ya s e n d i r i

  u n g u

  

  j a m b o n

   t i d a k b e r w a r n a . 

    (-) * k e k u at a n o k s i d a s i t e r g a n t u n g m e d i u m l a r u t a n ,

  a s a m , n e t r a l , b a s a k u at . & r e a k s i y g t e r j a d i

• K e s t a b i l a n l a r u t a n t e r b at a s
• d l m m e d i u m H Cl , K M n O

  4

  t e r o k s i d a s i o l e h Cl

• l a r u t a n s t a n d a r d s e k u n d e r (p e r l u s t a n d a r d i s a s i )
Pe n g g u n a a n K M n O

  4 1 . SUA SA N A A SA M 0 ,1 N

• 2 + + -

  M n O + 8 H + 5 e M n + 4 H O

  4

  2

• M n O4 - + 8 H O + 5 e - M n 2 + + 1 2 H 2 O

  3 7 + 2 +

  M n n = 5 Eo = 1 ,5 1 vo l t

    M n  

  2 . SUA SA N A N ET RA L

  M n O4 - + 4 H 3 O+ + 3 e - M n O + 6 H 2 O

  2 7 +

  M n   M n O

  2  n = 3 Eo = 0 ,1 6 9 5 vo l t 

  3 . SUA SA N A B A SA K UAT

• 2 -

  M n O + e M n O n = 1 Eo = 0 ,5 6 4 vo l t

  4

  4 L a r u t a n K M n O4 d l m a i r t d k s t a b i l  ai r t er ok s i das i 

  4 M n O + 2 H O 4 M n O + 3 O + 4 OH

  4

  2

  

2

  2 Pe r u r i a n d i k at a l i s a d a n ya : 2 +

  c a h a ya , p a n a s , a s a m , b a s a M n M n O

  2

  d e k o m p o s i s i s e n d i r i b e r s i f at a u t o k at a l i t i k

  STA N DA RDI SA SI K M n O

  4 o

  L a r u t a n (s t a n d r d 1 ) u t k s t a n d a r d i s a s i K M n O :

  4 Ok s a l at , N a o k s a l at  (banyak di gunak an), 

  A s O , K [ Fe (CN ) ] 3 H O, l o g a m b e s i d l l

  2

  3

  4

  6

  2 L a r t s t a n d p r i m e r h r s m u r n i s e c a r a k i m i a , s e s u a i d g r u m u s m o l , m u d a h d i m u r n i k a n .

  

N a C O m u d a h d i m u r n i k a n d g r e k r i s t a l i s a s i d a r i a i r

  2

  2

  4 o

  & p e n g e r i n g a n p a d a s u h u 2 4 0 – 2 5 0 C. t d k h i g r o s c o p i s d a n t d k b e r u b a h p d p e n y i m p a n a n .

  A s a m Ok s a l at a g a k l b h s u k a r d i m u r n i k a n k r n m e - n g a n d u n g a i r k r i s t a l  bi s a ber k em bang. n g a n d u n g a i r k r i s t a l  bi s a ber k em bang.

  U n t u k m e m p e r s i a p k a n l r t s t a n d K M n O h a r u s b e b a s

  4

  / d i h i n d a r k a n d a r i M n O

  2 Pe r s a m a a n Re a k s i s t a n d a r d i a s i K M n O4

• ) 2 N a C O + 2 K M n O + 8 H SO

  2

  2

  4

  4

  2

  4

  2 M n SO + K SO + 5 N a SO + 8 H O + 1 0 .CO

  4

  2

  4

  2

  4

  2

  2

• ) 5 H C O + 2 K M n O + 3 H SO

  2

  2

  4

  4

  2

  4

  2 M n SO + K SO + 8 H O 1 0 CO

  4

  2

  4

  2

  2 Da r i k e d u a r e a k s i i o n C2 O4 2 - t e r o k s i d a s i s b b 2 -

• C O

  2 CO + 2 e

  2

  4

  2

  s h g 1 g r e k a s Ok s a l at = 1 m o l

  [ l r t s t n d ] = 0 ,0 2 N 1 g r e k N a Ok s a l at = ½ m o l Co n t o h a p l i k a s i a n a l i s a a . L r t K M n O

  4

  p d T E Pe m e c a h a n s o a l : d e n g a n t i n j a u a n N o r m a l i t a s . a ) M e q K M n O

  / n

  4

  2 O

  x V = --------------------------- M r.N a

  K M n O4

  N

  2 O 4 (m g )

  p a d a T E W.N a

  4

  2 O

  2 C

  s e t a r a m e q N a

  4

  4

  d i s t a n d a r d i s a s i d g l r t s d t 1 o N a

  p a d a T E  hi t ung ber a pa N K M nO

  2 C

  2 O

  4 B i l a 2 8 2 m g N a o k s a l at m e m b u t u h k a n 3 5 ,8 7 m L

  K M n O

  4

  4

  p d T E  s a m p e l m e m b u t u h k a n 4 5 ,7 3 m L l r t K M n O

  b . L r t K M n O

  4

  (a ) d i p a k a i u t k m e n e n t u k a n M n

  2 +

  H i t u n g % M n d a l a m s a m p e l m i n e r a l , b i l a 4 8 7 ,4 m g s a m p e l m e m b u t u h k a n 4 5 ,7 3 m L l r t K M n O

  4

2 C

2 C

• =

  N a C O

  2 N a + C O

  2

  2

  4

  

2

  4

• =

  C O

  2 CO + 2 e n = 2

  2

  4

  2

  2 8 2 ,0 N x 3 5 ,8 7 = -------------- ] = 0 ,1 1 7 3 . N

   [ K M n O 

  4

  1 3 4 ,0 / 2 Da l a m s u a s a n a a s a m  n = 5  [ K M n O

  0 ,0 2 3 4 7 M 0 ,0 2 3 4 7 M

  [ K M n O ] d a l a m M o l a r  0,1173 / 5 =

  4 ] d a l a m M o l a r  0,1173 / 5 =

• 2 +

  b ) M e q M n s e t a r a m e q M n O p a d a T E

  4 Re a k s i y g t e r j a d i  

• 2 +
• 2 M n O + 3 M n + 4 OH

  5 M n O + 2 H O

  4

  2

  2 K e k u at a n o k s K M n O  3 /5 x 0 ,1 1 7 3 N = 0 ,0 7 0 4 N 

4 W.M n

  W.M n

  (m g ) (m g )

• = N x m L  -------------- = 0,074 x 45,73

   M r.M n / n 5 4 ,9 4 /2 8 8 ,4 4 W.M n

  = 8 8 ,4 4 m g  % = ------------ x 100 % =

  (m g ) 

  4 8 7 ,4 4 8 7 ,4 = 1 8 ,1 5 % 1 ) Co b a s e l e s a i k a n p e m e c a h a n s o a l d e n g a n

  T i n j a u a n k o n s e n t r a s i d a l a m m o l (M ) 2 ) Tu g a s m at e r i B i k r o m at o m e t r i d a n I o d o -i o d i m e t r i .

  B I K ROM ATOM ET RI T i t r a n 2 Cr O

  2 7  o k s i d at o r k u at . Eo = 1 ,3 3 vo l t 

• L r t s t n a d a r d p r i m e r
• St a b i l
• K e k u at a n o k s l e b i h l e m a h d a r i K M n O4 d a n Ce r r i
• Re a k s i l a m b at
• I n d i k at o r y g b i a s a d i g u n a k a n : a s d i f e n i l a m i n -s u l f n t • I n d i k at o r y g b i a s a d i g u n a k a n : a s d i f e n i l a m i n -s u l f n t

  B a d i f e n i l a m i n -s u l f n t

• K a r s i n o g e n  per l u penanganan hat i -hat i .  Re a k s i ya n g t e r j a d i :