kimia analitik
description
Transcript of kimia analitik
![Page 1: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/1.jpg)
Kuliah 7 . 2 April 2013
TITRASI REDOKS
![Page 2: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/2.jpg)
TITRASI REDOKS
Dasar RX : reaksi oksidasi-reduksi
Ox + ne- red
ox
red
nEE o log
0591,0
red
ox
nEE o log
0591,0
![Page 3: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/3.jpg)
Oksidasi : red1 ox1 + n1e
Reduksi : ox2 + n2e red2
n2 red1 + n1ox2 n2 ox1 + n1red2
1
1
111 log
0591,0
red
ox
nEE o
2
2
222 log
0591,0
red
ox
nEE o
2
2
1
122112211 log0591,0
red
oxx
red
oxEnEnEnEn oo
![Page 4: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/4.jpg)
Selama titrasi berlangsung
Eoksidator ; Ereduktor
TE:
Pd titik Ekivalent
E1 = E2 = E ekivalent
1
2
2
1
n
n
red
ox
2
1
1
2
n
n
red
ox
21
2211
nn
EnEnE
oo
ekivalent
022112211 EnEnEnEn o
0221121 )( EnEnEnn o
ekivalent
n2 red1 + n1ox2 n2 ox1 + n1red2
2
2
1
122112211 log0591,0
red
oxx
red
oxEnEnEnEn oo
![Page 5: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/5.jpg)
Hit Eekiv pd titrasi Fe+2 dgn KMnO4 dlm suasana asam
Oks : Fe+2 Fe+3 + e ........................... E1
Red : MnO4-+8H++5e Mn+2+4H2O … E2
5 Fe+2 + MnO4- +8H+ 5Fe+3 +1Mn+2+4H2O
Pd TE :
* E1 = E2 = E ekiv
* 1
52
3
Mn
Fe5
124
Fe
MnO
+
![Page 6: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/6.jpg)
5 Fe+2 + MnO4- +8H+ 5Fe+3
+1Mn+2+4H2O
Pd TE : * E1 = E2 = E ekiv
*
1
52
3
Mn
Fe5
124
Fe
MnO
2
3
11 log059,0
Fe
FeEE o
][
]][[log
5
0591,02
84
22
Mn
HMnOEE o
]][[
][]][[log059,055
22
384
2121
FeMn
FeHMnOEEEE oo
8021 ]log[059,056 HEEE o
ekiv
6
472,05 021 pHEE
Eo
ekiv
![Page 7: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/7.jpg)
soal
Hit Eekiv pada titrasi:
Fe+2 dengan K2Cr2O7 dlm
suasana asam
![Page 8: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/8.jpg)
Perhitungan
∑ grek oksidator = ∑ grek reduktor
[ V X N ]oksidator = [ V x N ] reduktor
1grek = 1 mol e- yg dilepas /diikat
5e- + 8H+ + 1 MnO4= Mn+2 + 4 H2O
1 mol MnO4= = 5 mol elektron
1 mol MnO4= = 5 grek
![Page 9: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/9.jpg)
Perhitungan nilai K suatu reaksi redoks
red1 ox1 + n1e
ox2+n2e red2
n2 red1+ n1 ox2 ⇄ n2 ox1+ n1 red2
Pd keadaan setimbang : E1 = E2
1
1
11
2
2
22 log
0591,0log
0591,0
red
ox
nE
red
ox
nE oo
2
2
21
1
112 log
0591,0log
0591,0
red
ox
nred
ox
nEE oo
x (n1n2)
1
1
111 log
0591,0
red
ox
nEE o
2
2
222 log
0591,0
red
ox
nEE o
![Page 10: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/10.jpg)
1
1
2
2
)(
)(
)(
)(log0591,0][
2
2
1
11221 n
n
n
noo
red
oxx
red
oxEEnn
2
21
1
121221 log0591,0log0591,0][
red
oxn
red
oxnEEnn oo
1
1
2
2
)(
)(log0591,0
)(
)(log0591,0][
2
2
1
11221 n
n
n
noo
red
ox
red
oxEEnn
KEnn log0591,021 0591,0/)( 2110 EnnK
n2 red1+ n1 ox2 n2 ox1+ n1 red2
![Page 11: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/11.jpg)
Penentuan titik akhir
1. Tanpa Indikator
2. Indikator redoks
![Page 12: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/12.jpg)
Tanpa indikator
Syarat: warna btk oksidasi ≠ btk reduksi
Permanganometri
Titran : KMnO4 dlm suasana asam
MnO4-+ 8H+ +5e- Mn+2 + 4H2O
Ungu tdk berwarna btk oks btk red
1 mol KMnO4 = 5 grek
![Page 13: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/13.jpg)
Lrt KMnO4 dlm air tdk stabil
4 MnO4- + 2 H2O 4MnO2↓+3 O2↑+ 4 OH-
Rx dikatalisir oleh cahaya,
* penyimpanan hrs dlm botol berwarna coklat
* Setiap pemakaian hrs dilakukan standarisasi
ulang
![Page 14: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/14.jpg)
Contoh
Titrasi Na2C2O4 dengan KMnO4
5C2O4=
+2MnO4-+ 16H+ 2Mn+2+10CO2+8H2O
Ttk akhir Titrasi
KMnO4
Na2C2O4
![Page 15: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/15.jpg)
Perhitungan
5C2O4=
+2MnO4-+ 16H+
2Mn+2+10CO2+8H2O
+3 +4 pbo C = 1 pbo total = 2 x 1 =2 1 mol Na2C2O4 = 2 grek
![Page 16: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/16.jpg)
Ada 2 tipe indikator
• Specifik : Bereaksi dgn zat kimia ttt yg
terlibat dlm titrasi • Umum : Sebagai fungsi Ecell
Indikator redoks
![Page 17: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/17.jpg)
Specifik
IODOMETRIK TITRASI
Langsung IODIMETRI
Titrant : I2
Tidak langsung: IODOMETRI Titrant : lrt Na2S2O3
analat : hrs st oksidator yg cukup kuat Indikator : amylum Amylum + I2 senyawa komplek berwarna biru
![Page 18: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/18.jpg)
IODOMETRI TDK LANGSUNG
REAKSI: 1. analat + KI I2
2. I2 + 2 S2O3-2 S4O6
-2 + 2 I-
b.o.S=2 b.o S=2,5 pbo total = 2x0.5
1 mol S2O3-2 = 1 grek
Dititrasi dgn tiosulfat
S2O3-2oksidator
![Page 19: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/19.jpg)
Perhitungan:
* analat + KI I2
Grek analat = grek I2 ..........(1)
* I2 + 2 S2O3-2 S4O6
-2 + 2 I-
Grek I2 = grek Na2S2O3 .......(2)
dr (1) dan (2) didpt:
Grek analat = grek Na2S2O3
(V x N)analat = (V x N) Na2S2O3
![Page 20: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/20.jpg)
BEBERAPA HAL YG HRS DIPERHATIKAN
1. Pelarut hrs bebas O2 dan CO2
* O2
Reaksi : O2+ 4 I-+4 H+ ⇄ 2 I2+2 H2O
* CO2 bersifat asam
S2O3-2 + H+ ⇄ H2S2O3
H2O
SO2
S
![Page 21: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/21.jpg)
2. pH
bila pH ↑ : I2 akan terhidrolisa menjadi hypoiodit
I2 + H2O ⇄ HIO + HI
hypoiodit mengoksidasi S2O3-2 SO4
-2
4 HIO + S2O3-2 + H2O ⇄ 2 SO4
-2 + 4 I- + H+
Bo S= 2 boS = 6
1 mol S2O3-2 = 8 grek
![Page 22: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/22.jpg)
3. I2 terikat kuat dgn amylum
Cara penambahan indikator:
* Analat + KI
* Titrasi I2 dgn tiosulfat sp lrt berwarna coklat muda
* tambahkan indikator amylum ( lrt berwarna biru tua)
* Titrasi dilanjutkan dgn tiosulfat sp warna biru tepat
hilang.
![Page 23: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/23.jpg)
Indikator sbg fungsi E cell
: indikator yg warnanya tgt pd Potensial lrt
Syarat:
* Indikator hrs berubah warna pd / dekat ttk ekivalent
* Warna btk oks ≠ warna btk red
In+n + ne- In
In
In
nEE
no
log0591,0
![Page 24: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/24.jpg)
In
In
nEE
no
log0591,0
Btk red
Btk oks
![Page 25: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/25.jpg)
Pd titrasi besi(II) dgn Cerium(IV) dalam
asam sulfat 1 M,
indikator apa yg dpt digunakan
Eo Fe+2 - Fe+3 = 0,68
Eo Ce+3 - Ce+4 = 1,44
21
2211
nn
EnEnE
oo
ekivalent
1,06 V
![Page 26: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/26.jpg)
INDIKATOR REDOKS
![Page 27: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/27.jpg)
IODATOMETRIHampir serupa dgn iodometri tdk langsung
Iodometri • Titrant: tiosulfat• Analat: KIO3
6 I- 3 I2 + 6e IO3
-+ 6 H+ + 6e I- + 3 H2
IO3-+ 6H++ 5I- 3 I2 + 3H2O
Indikator: amylum Ttk akhir titrasi:
warna biru tepat hilang 1 mol KIO3 = 6 grek
Iodatometri
* Titrant: KIO3 dlm HCl 4N * Analat : iodida
2 I- 2 I+ + 4e- IO3
- + 6 H++ 4e I+ + 3 H20
IO3- + 6H+ + 2I- 3 I+ + 3H20
Indikator: - Ttk akhir titrasi: perubahan warna CCl4/ CHCl3
Ungu (I2) - hilang - kuning (ICl)
1 mol KIO3 = 4 grek
![Page 28: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/28.jpg)
Analat kadang terdapat dalam lebih satu keadaan oksidasi.
harus diubah menjadi keadaan oksidasi tunggal sebelum dilakukan titrasi
Contoh:
besi ada dalam keadaan Fe+2 maupun Fe+3
Jadi harus direduksi secara lengkap menjadi
keadaan Fe+2 sebelum dititrasi
![Page 29: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/29.jpg)
Pereduksi yang umum
digunakan adalah Reduktor Jones Reduktor Perak
![Page 30: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/30.jpg)
soal
25.00 ml suatu larutan mengandung besi(III) dan Kromium(III) dilewatkan ke reduktor Jones dan kemudian dititrasi dengan 35,83 ml 0,1016 KMnO4 dalam larutan asam kuat. 25,00 ml larutan yang sama dilewatkan ke reduktor perak dan kemudian dititrasi dengan 14,65 ml KMnO4. Hitung M besi(III) dan Kromium(III) dalam larutan semula.
![Page 31: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/31.jpg)
soal
Berapa volum 0,0300 M KMnO4 yang diperlukan untuk bereaksi dengan 5,00 ml H2O2 dalam larutan asam yang mempunyai densitas 1,01 gr/ml dan mengandung 3,00%berat H2O2
![Page 32: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/32.jpg)
soal
Suatu contoh tembaga oksida berat 2,013 gr dilarutkan dalam asam.,pH diatur dan ditambah KI berlebih untuk membebaskanI2, dan I2 dititrasi dengan 29,68 ml 0,1058 N Na2S2O3. Hitung % CuO dalam contoh
![Page 33: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/33.jpg)
soal
Tentukan metoda yg tepat utk menentukan
kadar zat yg terdpt dlm larutan yg mgd
* NaHCO3
* Na2C2O4.
![Page 34: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/34.jpg)
I. DATA:NaHCO3 HCO3
- amfoter
Basa : HCO3- H2CO3
1 mol = 1 grek
Asam : HCO3- CO3
-2
1 mol = 2 grek
Titrant HCl
indikator: MO
Titrant NaOH (X)
Na2C2O4 C2O4-
BasaC2O4
-2 HC2O4
- H2C2O4
OksidasiC2O4
-2 2CO2 + 2e
Titrant: HCl (X)
Titrant KMnO4
![Page 35: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/35.jpg)
II. ANALISA
* Titrasi dgn HCl zat yg bereaksi: * HCO3
- H2CO3
1 mol HCO3-= 1 grek
* C2O4-2
ikut tertitrasi
C2O4-2
HC2O4- H2C2O4
xxxx
C2O4-2 hrs dipisahkan , sebelum titrasi
dgn HCl dilakukan
![Page 36: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/36.jpg)
II. ANALISA
Titrasi dgn KMnO4
Zat yg bereaksi:
C2O4-2
2CO2 + 2e
1 mol Na2C2O4 = 2 grek
Perhitungan:Grek KMnO4 = grek Na2C2O4
1 mol KMnO4 = 5 grek
![Page 37: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/37.jpg)
III. METODE
• Sebelum analisa dilakukan, lakukan pemisahan dgn pe+an CaCl2 sampai seluruh C2O4
-2 mengendap sbg CaC2O4
Reaksi:
C2O4-2
+ Ca+2 CaC2O4
HCO3- + Ca+2 CaHCO3
• Saring
![Page 38: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/38.jpg)
III. METODE
• Filtrat mgd CaHCO3
HCO3- ditentukan dgn
Titran : HCl Indikator : MO Reaksi:
HCO3- + H+ H2CO3
![Page 39: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/39.jpg)
III. METODE
• Endapan CaC2O4 dicuci,+ H2SO4 sampai
larutan bersifat asam lalu• titrasi dgn KMnO4
Grek KMnO4 = grek C2O4-2
1 mol KMnO4 = 5 grek
![Page 40: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/40.jpg)
IV : Pelaksanaan
1. Persiapan sampel
ambil 100 ml sampel , tambahkan
larutan CaCl2 sp tdk lagi terbentuk endapan
filtrat utk uji HCO3-
Filtrat + aquadest sp vol menjadi 250 ml dlm labu takar 250 ml
endapan utk uji C2O4-2
![Page 41: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/41.jpg)
100 ml sampel
CaCl2
CaC2O4
HCO3-
HCO3-
CaC2O4
![Page 42: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/42.jpg)
CaC2O4
100 ml sampel
CaCl2
HCO3-
250 ml
25 ml +MO dititrasi dgn 20 ml HCl 0,1N
HCO3-
![Page 43: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/43.jpg)
IV : Pelaksanaan
2. Persiapan larutan
3. Standarisasi
4. Penentuan kadar
5. Perhitungan
![Page 44: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/44.jpg)
IV : Pelaksanaan
* Penentuan kadar:• Penentuan kadar Na2C2O4
Prosedur : ↓ yg sdh dicuci di asamkan dgn H2SO4 di
titrasi dgn lar KMnO4 0,1N (mis: 10 ml)
• Perhitungan: mgrek Na2C2O4 = mgrek KMnO4
mgrek Na2C2O4 = 10 x 0,1 = 1 mgrek
Na2C2O4 = 0,5 mmol/100 ml
Na2C2O4 = 0,005 M
![Page 45: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/45.jpg)
IV : Pelaksanaan
Penentuan kadar NaHCO3
Filtrat + aquadest sp vol menjadi 250 ml dlm labu takar 250 ml
Prosedur: ambil 25 ml dr filtrat yg sdh diencerkan + ind MO dan titrasi dgn HCl 0,1N (mis 20 ml )Perhitungan: mgrek NaHCO3 = mgrek HCl 25 x N NaHCO3 = 20 x 0,1 N NaHCO3 = 0,08 M NaHCO3 = 0,08 dlm 250 ml lrt yg sdh
diencerkan
M NaHCO3 = 0,08
![Page 46: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/46.jpg)
IV : Pelaksanaan
M NaHCO3 = 0,08
100 x MNaHCO3 = 250 X 0,08
MNaHCO3 = 0,20
![Page 47: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/47.jpg)
TUGAS 1.
Naformiat bereaksi dengan permanganatdalam suasana netral menurut persamaanreaksi sbb:
CHO2- + MnO4
- + H2O MnO2(p) + CO2 + OH-
• Setarakan reaksi diatas• 0,500 gram contoh mengandung Naformiat dititrasi
dgn 50,00 ml 0,0600 M MnO4- ( berlebih)dlm
suasana netral. Larutan disaring utk diambil MnO2, kemudian diasamkan dgn H2SO4 dan dititrasi dengan 30,00 ml 0,1000M H2C2O4. Hitung % Na formiat dalam contoh tsb
![Page 48: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/48.jpg)
Jawab
CHO2- CO2 + H+ + 2e- ……..X3
3e- + 4H+ + MnO4- MnO2(p) + 2H2O ……..X2
3 CHO2- + 5H+ + 2MnO4
- 3 CO2 + 2 MnO2(p) + 2H2O
1 mol CHO2- = 2 grek
1 mol MnO4- = 3 grek
![Page 49: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/49.jpg)
0,500 gram contoh mgd Naformiat dititrasi dgn
50,00 ml 0,0600 M MnO4- berlebih ( ss netral)
Reaksi:
3 CHO2- + 5H+ + 2MnO4
- 3 CO2 + 2 MnO2(p) + 2H2O
1 mol CHO2- = 2 grek
1 mol MnO4- = 3 grek
Larutan disaring utk diambil MnO2, kemudian diasamkan
dgn H2SO4 dan dititrasi dengan 30,00 ml 0,1000M H2C2O4
Sisa MnO4- dititrasi dengan 30,00 ml 0,1000M H2C2O4.
![Page 50: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/50.jpg)
Reaksi 2.
H2C2O4 2CO2 + 2H+ + 2e- …………. X5
5e- + 8H+ + MnO4- Mn+2 + 4H2O ….. X2
5 H2C2O4 + 6H+ + 2MnO4- 10CO2 + Mn+2 + 8H2O
1 mol H2C2O4 = 2 grek
1 mol MnO4- = 5 grek
![Page 51: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/51.jpg)
MnO4- bereaksi dgn:
• Na formiat dlm suasana netral
1 mol CHO2- = 2 grek
1 mol MnO4- = 3 grek
• H2C2O4 dlm suasana asam
1 mol H2C2O4 = 2 grek
1 mol MnO4- = 5 grek
![Page 52: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/52.jpg)
Dr reaksi 2. 1 mol H2C2O4 = 2 grek
1 mol MnO4- = 5 grek
mgrek KMnO4 (sisa) = mgrek H2C2O4
= 30,00 ml 0,1000 x 2
= 6 mgrek
mmol KMnO4 (sisa) = (6/5)mmol
= 1,2 mmol
![Page 53: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/53.jpg)
Dr reaksi 1. 1 mol CHO2
- = 2 grek
1 mol MnO4- = 3 grek
total mmol KMnO4 = 50,00 ml 0,0600 = 3 mmol
mgrek CHO2- = mgrek KMnO4
= ( 3 – 1,2 ) x 3
= 5,4 mgrek
mmol CHO2- = (5,4/ 2 )mmol
= 2,7 mmol
CHO2Na = 2,7 x 91 = 245,7 mgr
= (245,7/500)x100%= 49%
![Page 54: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/54.jpg)
mmol KMnO4 :
= mmol KMnO4 (1) + mmol KMnO4 (2)
= 2 mmol + 1,2 mmol
= 3,2 mmol
= 3,2 x 158 mgr
= 505,6 mgr = 505,6/
![Page 55: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/55.jpg)
TUGAS 2.
Tuliskan metode yg tepat untuk menentukan
kadar campuran suatu zat yg mengandung:• CaCO3
• Na2HPO4
![Page 56: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/56.jpg)
DATA
* CaCO3 tdk larut dlm air
CO3-2 basa
CO3-2 HCO3
- H2CO3
• Na2HPO4 lrt dlm air
HPO4- basa
HPO4- H2PO4
-
HPO4- asam
HPO4- PO4
-3 XXXX
Titran : HCl
Ind : PP / MO
Titran : HCl
Ind : MO
![Page 57: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/57.jpg)
ANALISA
• CaCO3 tdk larut dlm air
• Na2HPO4 lrt dlm air
* Pisahkan CaCO3 berdasarkan perbedaan
kelarutannya dlm air
* Timbang 10 gram zat, larutkan dalam 250
ml H2O
* saring
![Page 58: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/58.jpg)
10 gr
H2O
250 ml
Na2HPO4
CaCO3
• Cuci sp bersih• Panaskan sp kering• Timbang• Panaskan • Timbang sp berat tdk
berubah lagi mis: 1 gr• Kadar CaCO3 = 10%
• Ambil 25 ml + ind MO
• Titrasi dgn lar HCl 0,1 M
mis : 20 ml HCl
![Page 59: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/59.jpg)
Perhitungan
Grek Na2HPO4 = grek HCl
(Vx N) Na2HPO4 = (V x N ) HCl
25 x NNa2HPO4 = 20 x 0,1
NNa2HPO4 = 0,08 N
MNa2HPO4 = 0,08 M
Na2HPO4 = 250 x 0,08 mmol
=2,840 gr
= (2,840/10)x100%
= 28,4%
![Page 60: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/60.jpg)
Tugas 3. Diketahui pasangan redoks berikut:
A+3 + e A+2 Eo = + 1,70 V
B+4 + 2e B+2 Eo = + 0,50 V
C+3 + e C+2 Eo = + 0,80 V
Titrasi mana yg mungkin dapat dilaksanakan:• A+2 dgn B+4
• A+3 dgn C+2
• A+2 dgn C+3
• C+2 dgn B+4
![Page 61: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/61.jpg)
Tugas 4.
Serbuk Penglantang Ca(OCl)Cl bereaksi dgn
ion Iodida dalam suasana asam dan
menghasilkan Iodium berdasarkan reaksi:
OCl- + I- + H+ I2 + Cl- + H2O
Bila 35,24 ml 0,1084 N Na2S2O3 diperlukan untuk
melakukan titrasi Iodium yang dibebaskan dari
0,6000 gr serbuk penglantang.
Hitung : % Cl dalam serbuk tsb.
![Page 62: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/62.jpg)
Tugas 5.
Sebuah contoh batu kapur mengandung 30,00%
CaO. Ca diendapkan sebagai CaC2O4, kemudian
diasamkan dengan H2SO4 dan dititrasi dgn
larutan standart KMnO4, dan diperoleh kadar CaO
sebesar 32,50% CaO dlm contoh tsb.Bila
kesalahannya disebabkan oleh pengendapan yg
telah terkontaminasi dgn MgC2O4,berapa %berat
endapan MgC2O4 yg ada
![Page 63: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/63.jpg)
Tugas 6.
35,00 ml larutan KIO3 bereaksi tepat dgn 35,00 ml 0,1000M larutan KI dalam suasana asam menurut pers reaksi sbb:
IO3- + I- + H+ I2 + H2O
50,00 ml KIO3 ini direaksikan dgn KI berlebih
dlm suasana asam dan I2 yg bebas dititrasi
dgn 0,1000 N Na2S2O3. Berapa volum titran yg diperlukan?
![Page 64: kimia analitik](https://reader033.fdocuments.net/reader033/viewer/2022061200/547874bfb4af9f56268b4830/html5/thumbnails/64.jpg)
Tugas 7
Pilihkan metode yg tepat untuk menentukan
kadar masing zat zat dalam larutan yg mgd:
• Na2C2O4
• NaOH
• Na3PO4