Noi Dung Giao Trinh Hptdinh Tinh Duoc Trung 2012
Transcript of Noi Dung Giao Trinh Hptdinh Tinh Duoc Trung 2012
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PHN I
L THUYT HA PHNTCH NH TNH
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BI 1
I CNG V HA HC PHN TCH NH TNH
Mc tiu
1. Trnh by uc cc phng php phn tch nh tnh.
2. Cc phn ng dung trong ha phn tch nh tnh.
3. Nu uc cc hthng phn tch caiton v anion.
Nhim vca phn tch nh tnh l xc nh cc nguyn t, cc ion, cc phn
tc trong thnh phn cht phn tch. Trong phm vi bi ny chgii thiuphn phn tch nh tnh cc ion v c trong dung dch.
1.CC PHNG PHP PHN TCH NH TNH
1.1.Phng php ha hc
L phng php nh tnh da trn cc phn ng ha hc. Phng php
ny khng cn trang thit b phc tp nn c s dng rng ri trong thc t.
Tuy nhin n khng pht hin c nhng lng cht tng i nh.
1.2.
Phng php vt l v ha l
L nhng phng php da trn cc tnh cht vt l v ha l ca cht cn
phn tch:
Phng php so mu ngn la: t cc hp cht d bay hi ca cc
nguyn t trn ngn la n gas khng mu ri quan st. V d: ngn la Na+
c mu vng, K+ c mu tm, Ba2+ c mu xanh lc nht.
Phng php dng c: l phng php dng my thit b hot ng theo
nhng nguyn l xc nh phn tch nh tnh. V d: quang ph hp th, sc
k,
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Phng php vt l v ha l c c nhy v chnh xc cao nhng
i hi trang thit b phc tp khng phi tt c c s u trang b c nn
phng php ha hc vn ng vai tr quan trng trong cng tc phn tch.
1.3.
Phn tch t v phn tch kh1.3.1.
Phn tch t
Cc phn ng dng trong phn tch nh tnh thng c tin hnh trong
dung dch. u tin ngi ta ha tan cht phn tch trong dung mi sau
cho dung dch tc dng vi thuc ththch hp.
V d: pht hin ion clorid, ngi ta ha tan mt lng NaCl trong nc,
sau nhthuc thl AgNO3vo.
1.3.2.
Phn tch kh
Cht kho st v thuc th u l dng rn.
un nng nhit cao
V d:mui Natri t ln trn ming platin nung di ngn la khng mu th
n chuyn sang mu vng; tng tmui Kali cho mu tm xanh; Strontium
cho mu cam; Barium cho mu xanh l.
Kt hp nhit v ha cht
V d:to ht mu ca Natri tetraborat (Na2B4O7, 10H2O) hay Natri
hydrophosphat ammonium (NaNH4HPO4.4H2O) bng cch kim chy (un
vi Na2CO3v KNO3).
Nghin cht rn vi thuc thrn. (do Flavitski ngh1898)
V d:nghin vi tinh thCobalt Sulfat trn bn bng svi 1 lng
Ammonium thiocyanat rn (NH4CNS) to phc (NH4)2[Co(CNS)4] c mu
xanh dng.CoSO4+ NH4SCN (NH4)2[Co(SCN)4] + (NH4)SO4.
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1.4.
Phn tch lng ln, bn vi, vi lng, siu vi lng
1.4.1.
Phn tch th:lng cht 0,1-1g hay 10-100 ml dung dch. Tin hnh
trong ng nghim , becher, bnh cu.
1.4.2.
Bn vi phn tch:0,01 0,1g cht rn hay 0,1 - 0,3 ml dung dch.1.4.3.Phn tch nh:(vi phn tch) vi mg cht rn hay 0,01 0,1 ml dung
dch.
1.4.4.Siu vi phn tch:lng cht phn tch rt nh (hng g). Thc hnh
di knh hin vi.
1.4.5. Phng php vi tinh th:thc hin trn gi mang thy tinh, quan st
ion hay nguyn t qua knh hin vi dng kt tinh.
1.4.6.Phn tch dng phn ng chuyn mu dung dch hay thu ta mu
Tin hnh trn giy v phn hy t t theo th t xc nh ca dung dch
kho st v thuc th. C th thc hin trn a s, mt knh ng h hay
chn s.
1.5.
Phn tch ring bit v phn tch h thng
1.5.1.
Phn tch ring bit
L xc nh trc tip mt ion no trong hn hp nhiu ion bng mtphn ng c hiu (phn ng ch xy ra i vi ring mt ion). C th ly
tng phn ring dung dch phn tch th ring tng ion, khng cn theo
mt th t nht nh no.
V d:tm Bi3+bng thuc th thioure c mu vng ti, Fe3+vi KSCN c
mu mu c trng.
Trong nhiu trng hp khng s dng c phng php phn tch
ring bit v khng phi tt c cc ion u c phn ng tht c hiu.1.5.2.
Phn tch h thng
L tin hnh xc nh cc ion theo mt thtnht nh. Mun phn tch
hthng mt hn hp nhiu ion, ngi ta thng dng cc thuc th nhm
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chia cc ion thnh nhiu nhm, mi nhm c thli c chia thnh cc phn
nhm v cui cng c tch ring thnh ion ring bit xc nh.
C hai hthng phn tch cation:
Hthng dng H2S. Hthng dng acid base.
2.CC PHN NG DNG TRONG PHN TCH NH TNH
2.1.Cc loi phn ng
2.1.1. Phn loi theo bn cht ha hc
Phn ng ha tan. V d:
CaCl2/nc = Ca2++ 2Cl-
CaCO3+ 2HCL = CaCl2+ CO2+ H2O
Phn ngkt ta. V d:
Ag++ Cl-= AgCl
Phn ng trung ha. V d:
Ba(OH)2+ 2HCL = BaCl2+2H2O
Phn ng to cht bay hi. V d:
NH4NO
3+ NaOH = NH
3+ NaNO
3+ H
2O
Phn ng oxy ha kh. V d:
2Mn2++ 5PbO2+ 4H+= 2MnO4+ 5Pb
2++ 2H2O
Phn ng to phc. V d:
Hg2++ 4I-= [HgI4]2-
2.1.2. Phn loi theo mc ch phn tch
Phn ng tch:
Nhm chia cc cht, cc ion thnh tng nhm nh, hay tch ring mt ion,mt cht dung cho phn ng xc nh.
Phn ng c trng hay xc nh nh:
Phn ng kha hay loi b ion cn tr.
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Phn ng m kha hoc ph phc gii phng ion cn tm.
Phn ng iu chnh pH mi trng ha tan, kt ta hoc trung ha
cht cn phn tch.
2.2.
nhy v tnh c hiu ca phn ngCc phn ng dng trong phn tch nh tnh cn phi nhanh, nhy, c
hiu, c du hiu d nhn bit nh kt ta, to mu, mu thayi trong cc
dung mi, hay cc iu kin phn ng, sinh kh c c im ring.), xy ra
hon ton. Tuy nhin, ty theo mc ch phn tch ch cn t mt vi yu cu
c th, khng nht thit phi c cc c tnh nu. Chng hn, khi tch
ring mt ion bng cch kt ta th phn ng phi hon ton. Nhng ch nh
tnh ion th khng cn phi nh vy.
Hai yu cu quan trng i vi mt phn ng nh tnh l nhy, c
hiu
2.2.1. nhy ca phn ng
L lng cht ti thiu c thpht hin bng phn ng trong iu kin
xc nh
C 2 cch biu th nhy:
nhy tuyt i hay gii hn pht hin: l lng cht nhnht, thng
tnh bng microgam ( 1mcg = 10-6g ) trong mu em thcn c pht
hin bng mt phn ng no .
nhy tng i: l nng gii hn (hay pha long gii hn ),
thng tnh theo gam/ml, cn c pht hin bng mt phn ng trong
iu kin xc nh
VD: phn ng kt ta xc nh Na+
bng thuc thStreng trong ng nghimc nhy tuyt i l 10 mcg, ngha l phi c ti thiu 10 mcg Na+trong
mu em th. Mt khc quan st c r rng trong ng nghim th th
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tch dung dch em tht nht l 0,5 ml. V vy nhy tng i bng 2 x
10-5g (Na+)/ml.
Cng phn ng nhng m thc hin bng cch soi tinh th di tnh hin
vi th thtch dung dch mu thchcn 0,001 ml, theo nhy tng ivn l 2x10-5g/ml (hay pha long l 1/50.000 so vi n vnng g/ml),
nhng nhy tuyt i sl 0,02 mcg (nhy hn 500 ln so vi phn ng
trong ng nghim).
V d trn y cho thy, nhy phthuc cch thc hin phn ng. Ngoi ra
nhy phthuc cc yu tnhit , nng , thuc th, sc mt ca cc
ion l
C mt s cch tng nhy phn ng. Chng hn, dung dch iod rt long
trong nc c mu vng kh nhn bit, nhng khi chit iod vo Cloroform
mu tm xut hin r rng.
2.2.2. Tnh c hiu ca phn ng
L trong nhng iu kin xc nh , c th dng phn ng (hay thuc th)
xc nh mt cht khi c mt cc cht khc. Tnh c hiu ca mt phn
ng c th biu th bng gi tr.
lng ion cn pht hin
F= -----------------------------
Lng ion l cng c mt
Tt nhin, F cng nh, phn ng cng c hiu.
V d: KI l thuc th dc hiu ca ion Hg2+
v n cho ta mu son HgI2rtd nhn ra, d nng Hg2+rt nh nm ln trong nhiu ion khc. Hn
na mu d dng bin mt nu cho d KI do to thnh phc [HgI4]2-tan v
khng mu.
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2.3.
Thuc th trong cc phn ng nh tnh
Yu cu ca thuc th trong phn tch: Phi tinh khit, nhy v c hiu.
tinh khit l yu cu quan trng nht, cc thuc th ha hc xp theo
tinh khit tng dn nh sau: Loi k thut thng lm nguyn liu ban u.
Loi tinh khit th nghim ha hc ni chung.
Loi tinh khit phn tch.
Loi tinh khit ha hc lm cht chun.
Loi tinh khit quang hc dng trong phn tch quang ph.
Thuc th theo tc dng phn tch: gm hai loi
Thuc th nhm: L thuc th c tc dng ging nhau ln mt nhm cc
ion. V d, HCl l thuc th ca nhm Ag+, Pb2+, Hg22+.
Thuc th chn lc: l thuc th c tc dng ging nhau trn mt s ion
m cc ion ny c th thuc cc nhm phn tch khc nhau. Chng hn,
NH3c th to phc tan v khng mu vi mt s ion nhiu nhm phn
tch.
Thuc th c hiu hay thuc th ring: l thuc th ch cho phn ng c
hiu vi mt ion hoc vi mt cht. V d: h tinh bt cho mu xanh ch
vi iod, dimethyglyoxim trong mi trng amoniac to thnh ch vi ion
Ni2+mt kt ta mu hng.
3.
PHN TCH NH TNH CATION THEO PHNG PHP ACID
BASE
C 2 ng li ch yu phn tch h thng cc cation l ng li theo
phng php dng H2S v ng li theo phng php acid base.3.1.H thng dng H2S
Nguyn tc:to ta vi cc thuc th nh : HCl, H2S, (NH4)2S/ NaOH,
(NH4)2CO3
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Cc cation c chia thnh 5 nhm ty theo thuc thchung ca nhm.
u im:kh cht ch, kt qukh chnh xc, pht hin trit cc cation.
Nhc im:H2S rt c, mi kh chu, hay gp dung dch keo ca S.
3.2.
H thng dng acid - baseNguyn tc: Cc cation to ta hay to phc vi cc acid HCl, H2SO4 hoc
vi cc base nh NaOH, NH4OH.
u im:
t c hi hn hthng dng H2S
Sdng c nhng tnh cht c bn ca cc nguyn t: quan hca cc
nguyn tny vi cc acid v base, tnh lng tnh ca cc hydroxyd v
kh nng to phc ca cc nguyn t.
Thi gian thc hin phn tch ngn hn t30 40% so vi hthng H2S
Nhc im:Phn chia nhm khng cht chbng hthng dng H2S
Phn nhm cc cation
Nhm Ion Thuc th Kt qu
I Ag+, Pb2+, Hg22+ HCl 6M Ta clorid
II Ba
2+
, Ca
2+
H2SO43M/ cn 90
o
Ta sulfat
III Al3+, Zn2+ NaOH dHydroxyd tan/ kim
d
IV Bi3+, Fe3+, Mg2+NaOH, NH4OH
+ H2O2
Hydroxyd khng tan/
kim d
V Cu2+, Hg2+ NH4OH Phc tan/ NH4OH d
VI Na+, K+, NH4+ Chuyn bit
4.
PHN TCH NH TNH ANIONDo khng c thuc thnhm r rng nn cng khng thphn chia mt cch
cht chton bcc anion thnh nhng nhm ring phn tch hthng
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ging nh cc cation. Da theo tc dng thuc thnhm anion c th c phn
loi theo bng 1.1.
Phn nhm cc anion
C ba phng php: phn tch hthng, na hthng v ring bit.
Bng1.1.Phn loi thuc th theo nhm anion
Nhm Ion
I Cl-, Br-, I-, S2-, NO3-
II PO43-, HCO3-, CO3
2-, AsO33-, AsO4
3-
III SO42-, SO3
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TT Thuc thnhm Nhm anion Sn phm hoc du hiu phn
ng
1
HCl 2N hay
H2SO4
CO32-; CN-; S2-;SO3
S2O32-; NO2
-; ClO-
To cc kh tng ng:
CO2(khng mu, lm c nc
vi trong); HCN(mi hnh
nhn); H2S(mi thi); SO2(mi
sc mnh); SO2v S; NO v
NO2(mu nu , kh th); Cl2
(mu vng lc, kh th)
2
BaCl2+ CaCl2trong mi trng
trung tnh
AsO33-; AsO4
3-; CrO42-;
ClO
-
; MnO4-
; SO42-
;PO4
3-; BrO3-; IO3
-; F-
To kt ta tng ng:
Ca3(AsO3)2trng; Ca3(AsO4)2trng; BaCrO4vng; Ba(MnO4)2
; BaSO4trng; Ca3(PO4)2
trng; Ba(BrO3)2trng; Ba(IO3)2
trng; CaF2trng:
3
AgNO3+ HNO3
2N
SCN-;Cl-; Br-; I- To kt ta tng ng:
AgSCN trng; AgCl trng; AgBr
vng nht; AgI vng r4 Hn hp Mg
(NH4OH +
NH4Cl + Mg Cl2)
AsO43-; PO4
3- To kt ta tng ng:
MgNH4AsO4trng; MgNH4PO4
trng.
5
KI + H2SO42N
CrO42-; AsO3
3-; MnO4-;
ClO-; ClO3-; BrO3
-;
IO3-; NO2
-
Gii phng I2
(Nhn bit iod bng mu trong
dung dch nc hoc trong
cloroform, hoc thbng htinh
bt).
6 Dung dch I2 S2-; SO3
2-; S2O32-; Lm mt mu I2
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AsO33-
7 Dung dch
KMnO4+ H2SO4
2N
S2-; SO32-; S2O3
2-;
AsO33-; NO2
-; Cl-; Br-:
I-; CN-; SCN-
Lm mt mu KMnO4
8 Khng c thuc
thnhm
NO3-; ClO4
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BI 2
XC NH CC CATION NHM I
(Ag+, Pb2+, Hg22+)
MC TIU
1. Trnh by c tn, cng thc ha hc ca TT nhm, TT cation, hin tng
c trng khi cation nhm I tc dng cc TT v vit phng trnh ion
minh ha.
2. Thao tcng kthut th v xc nh cation nhm I.
1.
Thuc thnhm
1.1. Thuc thnhmCc cation nhm ny c kh nng to kt ta vi hu ht cc acid (trHNO3)
nhng ch c HCl 6N th to ta vi nhm ny m khng to ta vi cc
cation nhm khc. V th acid hydrocloric nng 6M (HCl 6M) chnh l
thuc th tch nhm cation Ag+, Pb2+, Hg22+ra khi cc cation khc.
Cc cation nhm I tc dng vi acid hydrocloric 6M to thnh cc kt ta
trng, cc kt ta ny c tnh cht khc nhau trong amoni hydroxyd (NH4OH).
1.2. Phng trnh ionAg++ HCl = AgCl+ H+
AgCl tan trong dung dch NH4OH
Pb2++ 2HCl = PbCl2+ 2H+
PbCl2khng tan trong dung dch NH4OH
Hg22++ 2HCl = Hg2Cl2+ 2H
+
Hg2Cl2ha en trong dung dch NH4OH
2.
Thuc thcation
2.1. Thuc thca ion Ag+:Vi cc dung dch ca
2.1.1. Kali cromat (K2CrO4):Ag+to ra kt ta thm.
2Ag++ K2CrO4= Ag2CrO4+ 2K+
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2.1.2. Kali iodid (KI):Ag+to kt ta vng nht.
Ag++ KI = AgI+ K+
2.1.3. Natri carbonat (Na2CO3): to ra kt ta trng, lu ha xm (do
phn hy thnh Ag2O).
2.2 Thuc thca ion Pb2+
2.2.1. Amoni sulfur [(NH4)2S] hay hydrosulfur (H2S):Pb2+ to ra kt ta
en.
Pb2++ (NH4)2S = PbS+ 2NH4+
Pb2+ + H2S = PbS+ 2H+
2.2.2. Kali cromat:Pb2+ to ra kt ta vng ti, ta ny tan trong dung dch
acid nitric, dung dch natri hydroxyd, khng tan trong acid acetic.
Pb2++ K2CrO4 = PbCrO4+ 2K+
2.2.3. Kali iodid:Pb2+ to ra kt ta vng, ta ny tan trong nc nng, khi
ngui li kt ta tinh thmu vng ng nh.
Pb2++ 2KI = PbI2+ 2K+
2.2.4. Acid sulfuric long (H2SO4 3M):Pb2+ to ra kt ta trng.
Pb2++ H2SO
4=
PbSO
4+ 2H+
2.2.5. Natri carbonat:to ra kt ta trng.
Pb2++ Na2CO3 = PbCO3+ 2Na+
2.3 Thuc thca ion Hg22+
2.3.1. Amoni hydroxyd:Hg22+to ra kt ta xm en (Hgonguyn t).
Hg22++ 2NH4OH = Hg2(OH)2+ 2NH4
+
2.3.2. Kali cromat:Hg22+ to ra kt ta mu gch.
Hg22+
+ K2CrO4= Hg2CrO4 + 2K+
2.3.3. Kali iodid:Hg2
2+ to ra kt ta mu xanh lc, nu d TT th chuyn
thnh mu en (Hgonguyn t)
Hg22++ 2KI = Hg2I2+2K
+
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Hg2I2+ 2KI = Hgo+ K2[HgI4]
2.3.4. Natri carbonat:Hg22+ to ra kt ta xm en
Hg22++ Na2CO3= Hg2CO3+2Na
+
Bng1.2. Tm tt cc phn ng c trng ca cation nhm ICationThuc th
Ag+ Pb2+ Hg22+
HCL long AgCltrng, tan
trong NH4OH d
do to phc
[Ag(NH3)2]+
PbCl2trng,tan
trong nc nng
HgCl2trng, tc
dng vi NH4OH
to Hg0+ NH2HgCl
H2SO4
long
- PbSO4trng Hg2SO4trng
NaOH hay
KOH
Ag2Oen Pb(OH)2trng, tan
trong kim d, to
PbO22-
Hg2Oen
NH4OH d To phc
[Ag(NH3)2]
+
Pb(OH)2trng [Hg2ONH2]NO3 +
Hg
0
K2CO3hay
Na2CO3
Ag2CO3trng Pb2(OH)2CO3trng Hg2CO3 = HgO +
Hg +CO2
K2CrO4 Ag2CrO4nu PbCrO4vng tan
trong kim d
HgCrO4
KI AgIvng PbI2vng tan trong
nc nng
Hg2I2vng, xanh,
nu d thuc th s
to thnh HgI42- +Hg0
H2S Ag2Sen PbSen HgSen+ Hg0
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CU HI N TP
1. Trnh by tn, cng thc ha hc ca TT nhm, hin tng c trng khication nhm I tc dng vi TT nhm v vit phng trnh ion minh ha?
2. Ktn, cng thc ha hc, hin tng c trng ca cc TT xc nh ion
Ag+, Pb2+, Hg22+v vit phng trnh ion minh ha.
3. K tn cc thuc thging nhau ca ion Ag+, Pb2+, Hg22+v hin tng
khc nhau khi cc TT tc dng vi ion Ag+, Pb2+, Hg22+?
4. Hy sdng bng kim c khng tkim tra kthut thv xc
nh cation nhm I?
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Bi 3
XC NH CATION NHM II
(Ba2+, Ca2+)
MC TIU
1. Trnh by c tn, cng thc ha hc ca TT nhm, hin tng c trng
khi cation nhm II tc dng vi TT nhm v vit phng trnh ion
minh ha.
2. K c tn, cng thc ha hc, hin tng c trng ca TT xc nh
cation Ba2+, Ca2+v vit phng trnh ion minh ha.
3. Thao tc ng k thut thcation nhm II vi cc TT ca chng v xcnh ng cation nhm I, II.
1. Thuc thnhm
1.1. Thuc th nhm
Acid sulfuric 3M (H2SO43M).
Cc cation nhm II tc dng vi TT acid sulfuric 3M to ra kt ta trng.
Trong cc phn ng ta ny ion Ba2+khng cn iu kin no, cn mun ta
ion Ca2+th phi cn mi trng aceton hoc ethanol 960. Tuy nhin nngcao Ca2+ c th to ta vi SO4
2-m khng cn mi trng aceton hoc
ethanol 960.
1.2. Phng trnh ion
Ba2++ H2SO4 = BaSO4+ 2H+
Ca2++ H2SO4 = CaSO4 + 2H+
2.
Thuc thcation
2.1. Thuc thca ionBa2+: vi cc dung dch ca
2.1.1. Kali cromat: Ba2+ to ra kt ta mu vng ti, ta ny khng tan
trong NaOH 3M v CH3COOH.
Ba2++ K2CrO4 = BaCrO4+ 2K+
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5. Hy sdng bng kim c khng tkim tra kthut thcc cation
nhm II vi cc TT ca chng v xc nh cation nhm I, II?
Thuc th Ba2+ Ca2+
H2SO43M
K2CrO4
Phn ng Voller
(NH4)2C2O4
Na2CO3
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BI 4
CATION NHM III (Al3+, Cr3+, Zn2+)
Mc tiu
1. Trnh by c tn, cng thc ha hc ca thuc th nhm, thuc th
cation, hin tng c trng khi cation nhm III tc dng vi cc nhm
thuc th v vit c cc phng trnh ion minh ha.
2. Bit cch xc nh cc ion nhm III thn hp cc cation nhm I, II, v
nhm III. V trong cc hn hp ion bt k.
1. C IM
Cc cation nhm III phn ng vi kim to kt ta hydroxyt mu trng
Al(OH)3, Cr(OH)3 v Zn(OH)2. Ta tan trong kim tha to thnh
aluminat (AlO2-), cromit (CrO2), zincat (ZnO2
2-).NaOH d l thuc thnhm
ca cation nhm III. Trong dung dch Zn2+, Al3+ khng mu, Cr3+ c mu
xanh tm. Zn2+ tn ti di 2 dng Zn2+v ZnO22- , Al3+ tn ti di dng
Al3+
hay AlO2-
, Cr3+
dng cation, kt ta Cr(OH)3 pH = 5, tan trong mitrng kim d. pH = 12,5 cho cromit mu xanh en.
2. PHN NG CHUNG
TC DNG VI KIM NATRI V KALI
Cho kt ta hydroxyd mu trng
Al3+ + 3NaOH Al(OH)3 + 3Na+
Cr3+ + 3NaOH Cr(OH)3 + 3Na+
Zn2+ + 2NaOH Zn(OH)2 + 2Na+
Cc hydroxyd c tnh lng tnh, tan trong kim thhin tnh acid.
Al(OH)3 + OH- AlO2
- + 2H2O
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Cr(OH)3 + OH- CrO2
- + 2H2O
Zn(OH)2 + OH- ZnO2- + 2H2O
V tan trong acid, trng hp ny cc hydroxyd thhin mt base.
Al(OH)3 + H+ Al3+ + 3H2O
Cr(OH)3 + H+ Cr3+ + 3H2O
Zn(OH)2 + H+ Zn2+ + 2H2O
3. PHN NG NH TNH
3.1. ION Al3+
Vi NaOH
To thnh ta keo Al(OH)3. Ta tan trong lng tha NaOH to thnhaluminat
Al3+ + 3NaOH Al(OH)3 + 3Na+
Al(OH)3 + OH- AlO2
- + 2H2O
Khi thm NH4Cl vo dung dch aluminat s xut hin ta tr li. Phn ng
ny gi l phn ng thy phn aluminat. y l phn ng c dng tch
Al3+ra khi hn hp cation nhm III.
Vi thuc thnhm Aluminon (amoni aurintricarboxylat)To mui ni phc c mu . Ty nng ca Al3+sc ta bng hay
dung dch mu . Phn ng thc hin trong mi trng acid yu pH = 4 5
vi m acetat acetic
Al3+ + aluminon + m acetat ta bng .
3.2. ION Cr3+
3.2.1.
Vi NaOH
To ta hydroxyd crom mu xanh en
Cr3+ + 3NaOH Cr(OH)3 + 3Na+
Hydroxyd crom tan trong lng tha NaOH to thnh cromit mu xanh nht
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Cr(OH)3 + NaOH NaCrO2 +
2H2O
Cromit khi un si sbthy phn cho li ta hydroxyd cromit.
3.2.2. Phn ng oxy haCr3+phn ng vi oxy gi trong mi trng kim to thnh cromat c mu vng
c trng.
2Cr3+ + 3H2O2 + 10NaOH CrO42- +
8H2O
3.2.2.
Phn ng to ngc c mu
Cr3+phn ng to ngc c mu sc khc nhau vi cc mui khc nhau nh
vi natriborat hay natrihydro phosphat to ngc c mu xanh l m, trng
hp nung chy mu cha Cr3+vi hn hp bt Na2CO3 v KNO3ngc c mu
vng.
3.3. ION Zn2+
3.3.1.Vi NaOH
Ion Zn2+phn ng vi NaOH cho ta km hydroxyd, ta tan trong kim d
to thnh zincat khng mu.
Zn2+ + 2NaOH Zn(OH)2 + 2Na+
Zn(OH)2 + 2NaOH Na2ZnO2 + 2H2O
3.3.2.Vi NH4OH
To thnh Zn(OH)2tan trong lng tha NH4OH to thnh phc [Zn(NH3)4].
Phn ng ny dng tch nhm ra khi hn hp c km trong cation nhm
III
3.3.3.
Vi thuc thM.T.A(MercuriThiocyanatAmoni)(NH4)2[Hg(SCN)4]Trong mi trng trung tnh hay acid nh, ion Zn2+ cho ta Zn[Hg(SCN)4]
mu trng. Nu thm vo dung dch Zn2+1 git Cu2+, khi cho M.T.A vo s
to thnh ta tm sim.
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Zn2+ + Cu2+ + 2[Hg(SCN)4]2- ZnCu[Hg(SCN)4]2
Mu ca ta ty thuc vo lng Cu2+thm vo.
t Cu2+ tm nht
Hi tha tm en
Tha nhiu xanh vng ca Cu2+.
CU HI N TP
1.Nu c tnh quan trng nht ca cation nhm III?
2. Vit cng thc ha hc, phn ng c trng ca cc ion , Al3+, Cr3+, Zn2+
3. So snh sging v khc nhau ca cc ion Al3+, Zn2+khi tc dng vi cc
thuc thv vit phng trnh ion minh ha?
4. So snh sging v khc nhau ca cc ion ca cc ion Al3+, Cr3+khi tc
dng vi cc thuc th v vit phng trnh ion minh ha?
5. Hon thnh cc phng trnh phn ng sau:
Al3+ + ............................ Al(OH)3 + 3Na+
Cr(OH)3+ NaOH ................. + 2H2O
Zn(OH)2+ 2NaOH ................. + 2H2O
6. Lm th no tch cc cation nhm III ra khi hn hp cc cation nhmI v II
7. Lm th no tch Al3+ra khi hn hp cation nhm III?
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BI 5
CATION NHM IV (Fe3+, Mn2+, Mg2+,Bi3+)
Mc tiu
1. Trnh by c tn, cng thc ha hc ca thuc thnhm, thuc th nh
tnh ca cc cation, hin tng c trng khi cation nhm IV tc dng vi
cc thuc th v vit c cc phng trnh ion minh ha.
2. Bit cch phn tch cc ion nhm IV thn hp cc cation nhm I, II, III
v nhm IV.
Ni dung
1.
C TNH C
A CATION NHM IV
Cc cation nhm IV tc dng vi kim cho ta hydroxyd khng tan trong
kim d.
Thuc thnhm: NaOH 3M v H2O2.
Trong dung dch cc ion khng mu trFe3+c mu vng nu
Tnh oxy ha kh. Cc cation nhm IV tham gia phn ng vi oxy ha kh.
Fe3+l cht oxy ha, bkhthnh Fe2+.
Mn2+
l cht khb oxy ha n Mn7+
c mu tm. Mg2+bkhvMg0.
Bi3+bkh n Bi0nguyn t c mu en.
2.
PHN NG CHUNG
Vi KOH, NaOH, NH4OH
Fe3 + 3OH- Fe(OH)3
Mg2+ + 2OH- Mg(OH)2
Mn2+ + 2OH- Mn(OH)2
B3+ + 3OH- Bi(OH)3
3.
PHN NG NH TNH
3.1. ION Fe3+
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3.1.1.
Vi NaOH
Cho ta mu nu, khng tan trong kim d, tan trong acid v c.
Fe3+ + 3NaOH Fe(OH)3
3.1.2.
Vi kali ferrocyanid K4[Fe(CN)6]
Trong mi trng acid Fe3+to ra kt ta keo mu xanh ph.
Fe3+ + K4[Fe(CN)6] Fe4[Fe(CN)6]3
Phn ng ny rt nhy, lng ti thiu tm thy (1 2 git): 0,05g, nng
gii hn 1: 1x106.
3.1.3.
Vi kali sulfocyanat KSCN
Fe3+ tophc mu mu. Thnh phn ca phc thay i ty theo nng
ion SCN- Fe3+ + 3KSCN Fe(SCN)3 + 3K+
3.2. ION Mn2+
3.2.1.
Vi NaOH, NH4OH
Cho kt ta Mn(OH)2trng, Mn(OH)2tan mt t trong kim d do to thnh
phc hydroxo Mn(OH)3-tan trong acid v c.
Mn2+ + 2OH- Mn(OH)2
Mn(OH)2dboxy ha trong khng kh to thnh MnO(OH)2c mu nu.3.2.2.
Phn ng oxy ha
Oxy ha Mn2+bng PbO2trong mi trng acid, to thnh Mn7+c mu tm
.
2Mn2 + 5PbO2 + 4H+ 2MnO4
- + 5Pb2++ 2H2O
3.3. ION Mg2+
3.3.1.
Vi NaOH
Ion Mg2+
cho ta trng Mg(OH)2, khng tan trong kim tha, tan trongNH4OH.
Mg2+ + 2OH- Mg(OH)2
3.3.2.Vi NH4OH
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Cho ta trng Mg(OH)2, nu c shin din ca NH4Cl th Mg(OH)2 khng
kt ta c.
3.3.3.
Phn ng vi Na2HPO4
Mg2+ to vi Na2HPO4 ta v nh hnh. Nu phn ng xy ra vi s hindin ca NH4OH NH4Cl scho ta tinh thc hnh sao ca MgNH4PO4,
6H2O
Mg2+ + NH4+ + PO4
3- NH4MgPO4
3.3.4.
Vi vng Thiazol
Trong mi trng kim NaOH, Mg2+ to vi vng thiazol ta nh tm.
Mg2+ + vng Thiazol + NaOH ta nh tm
3.4.ION Bi3+
3.4.1.Vi NaOH
Bi3+ cho ta keo Bi(OH)3 mu trng, ta khng tan trong kim d, tan trong
acid, un nng ta sc mu vng.
Bi3+ + 3OH- Bi(OH)3
3.4.2.Phn ng thy phn
Khi pha long dung dch mui Bi
3+
to thnh ta trng ca mui bismutyl, tantrong acid long.
Bi3+ + Cl- + H2O BiOCl + 2H2O
3.4.3.
Vi Kali Iodid
Bi3+ cho ta en BiI3, ta tan trong KI thnh phc [BiI4] mu cam.
Bi3+ + 3KI BiI3 + 3K+
BiI3 + KI K[BiI4]
3.4.4.
Vi ThioureCc mui to vi thioure mt phc mu vng.
Bi3+ +2SC(NH2)2 [Bi(NH2-CS-NH2)3]3+ dung dch mu
vng.
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BI 6
CC PHNG PHP XC NH CATION NHM V
(Cu2+, Co2+, Hg2+)
Mc tiu
1. Trnh by c tn, cng thc ha hc ca thuc thnhm, thuc th nh
tnh, hin tng c trng khi cation nhm V tc dng vi cc thuc th
v vit c phng trnh ion minh ha.
2. Bit cch tch nhm V ra khi hn hp cc cation v sdng cc phn
ng c trng nhn bit cc cation nhm ny.Ni dung
1. c tnh
Cation nhm V to vi kim nhng hydroxyd khng tan trong kim d nhng
tan trong NH4OH hoc hn hp NH4OH - NH4Cl thnh cc amonicat.
Thuc thnhm: NH4OH 3M.
Cc hydroxyd KOH v NaOH vi dung dch cha cation Cu2+ cho kt ta
hydroxyd lng tnh, vi Hg2+ cho oxyd, vi Co2+ cho mui base.Cc cation nhm V c c trng bi kh nng to phc, trong dung dch
mui Hg2+khng mu; mui Cu2+, Co2+ c mu.
2.
Phn ng chung
Vi KOH, NaOH
Cation nhm V to thnh cc hydroxyd c mu khc nhau
Cu2++ 2KOH Cu(OH)2 Xanh lam+ 2K2+
Co2++ KOH + Cl-CoOHCl Lam+ K2+
Hg2++ 2KOH HgO Vng+ 2K2++H2O
Cc ta ny tan trong acid v c v trong amoniac d
Vi NH4OH
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Dung dch amoniac d phn ng vi cation nhm V to cc phc
Cu2++ 4NH4OH [Cu(NH3)4]2++ 4H2O
Co2++ 6NH4OH [Co(NH3)6]2++ 6H2O
Hg2++ 4NH4OH [Hg(NH3)4]2++ 4H2O
Cc amonicat bn tr amonicat ca Cobalt, di tc dng ca oxy trong
khng kh schuyn thnh Co3+c mu tm.
3. Phn ng nh tnh
Ion Cu2+
Vi amoni hydroxyd: Cu2+ to kt ta mu xanh l tan khi cho NH4OH
d, to phc cht mu xanh lam
Cu2++ 2NH4OHCu2(OH)22+ + 2NH4
+
Cu2(OH)22++ 8 NH4OH 2[Cu(NH3)4](OH)2+ 4H2O
Vi Kali ferrocyanid: Cu2+cho kt ta ng ferrocyanid mu thm
Cu2++ K4[Fe(CN)6]Cu2[Fe(CN)6]
Vi thuc th M.T.A (Mercuri Thiocyanat Amoni): Cu2+ phn ng vi
thuc thMTA cho ta xanh vng. Nu thm vo dung dch Cu2+mt lng
Zn2+, ta to thnh c mu tm sim.
Cu2++ Zn2++ 2[Hg(SCN)4]2-
ZnCu[Hg(SCN)4]2 tm sim
Vi Na2S2O3: Na2S2O3khi thm vo dung dch mui ng acid ha s
lm mt mu dung dch do to thnh Cu2S khng tan trong acid.
2Cu2++ 2Na2S2O3 + 2 H2O Cu2S + 2Na2S4O6
Ion Co2+
Vi NH4OH: Co2+cho mui kim CoOH+mu xanh lam, khi un nng hay
phn ng vi NaOH bin thnh Co(OH)2 mu hng, tan trong NH4OH dthnh phc mu vng nu.
Co2++ NH4OH CoOH+Co(OH)2
Co(OH)2+ NH4OH [Co(NH3)4]2++ H2O
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Vi NH4SCN: cho mu xanh m vi Co2+do to phc dphn hy trong
nc v trong acid long, tan trong dung mi hu c nh aceton.
Co2++ NH4SCN [Co(SCN)4]2+
Ion Hg2+Vi NaOH: Hg2+phn ng vi kim to ta oxyd thy ngn mu vng.
Hg2++ NaOH HgOvng
Vi NH4OH: cho kt ta trng HgNH2+tan trong NH4OH d thnh phc.
Hg2++ NH4OH HgNH2+ (Mercuri amido)
HgNH2+ + NH4OH [Hg(NH3)4]
2+
Vi Kali Iodid: Hg2+phn ng vi KI cho ta HgI2mu cam, tan khi
cho d KI to phc mu vng nht.
Hg2++ 2KI HgI2cam+ 2K+
HgI2 + 2KI K2[HgI4]
Phn ng khvi SnCl2: Hg2+phn ng vi dung dch SnCl2mi pha cho
ta trng thy ngn I, sau chuyn thnh Hg nguyn t mu xm en.
Hg2++ SnCl2Hg2 + SnCl4Hg0
Vi Na2S
2O
3: trong mi trng acid, khi un nng Na
2S
2O
3 to vi mui
thy ngn II kt ta en thy ngn II sulfur (khng tan trong acid long).
Hg2++ Na2S2O3HgS en
CU HI N TP
1.Nu tn, cng thc ha hc ca thuc thnhm V, phn ng xy ra khi cho
cation nhm V tc dng vi thuc thcha nhm?
2.Vit cng thc ha hc, hin tng c trng v phng trnh ion minh ha
ca cc phn ng nh tnh cc ion Cu2+
, Co2+
v Hg2+
?3.Phn bit Cu2+v Co2+bng thuc thno? Vit phng trnh phn ng?
4.Lm th no tch cc cation nhm V ra khi hn hp cc cation nhm I,
II, III, IV, VI v trong dung dch bt k?
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BI 7
CC PHNG PHP XC NH CATION NHM VI
(NH4+, K+, Na+)
Mc tiu
1. Trnh by c tnh cht c bit ca cation nhm VI, cng thc ha hc
ca thuc th cation, hin tng c trng khi cation nhm VI tc dng
vi cc thuc th v vit c cc phng ion minh ha.
2. Bit cch xc nh cc ion nhm VI thn hp cc cation nhm I, II, III,
IV, V, VI v trong hn hp ion bt k.
3.Nu c s khc nhau c bn ca cation nhm VI vi cc cation 5 nhmu khi tc dng vi natri cacbonat.
Ni dung
1. C TNH CHUNG CA CATION NHM VI
Cc ion Na+, K+l cc ion kim loi kim, ion NH4+do phn tNH3v ion H
+
to nn NH4+khng bn trong dung dch kim v nhit cao.
HNH3
4NH
OHNH4 OHNH 23
Cc hp cht hydroxyd (NaOH, KOH, NH4OH), cc mui (clorid, sulfat,
carbonat) u d tan trong nc. Do khi dng acid hoc kim lm thuc
th nhm th cc cation ca 5 nhm u u kt ta, cn cation nhm VI
khng cho ta. Cation nhm VI khng c nhm thuc th nhm. xc nh
cc cation nhm VI ngi ta tin hnh xc nh trc tip cation m khng
phn tch theo hthng.
2. PHN NG NH TNH
2.1. ION NH4+
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2.1.1. Vi NaOH: ion NH4+bNaOH phn tch thnh amoniac NH3, kh ny
bay ra c thnhn bit bng giy tm phenolphtalein, giy sc mu hng,
hoc dng giy qutm sha xanh.
NH4++ NaOHNH3 + Na++ H2ONH3 + giy tm phenolphtalein hng.
NH3 + giy qutm xanh
2.1.2. Vi thuc thNessler: trong mi trng kim NH4+cho ta mu
nu hay vng nu.
KOHHgIKNH 32 2424 7KI + 2H2O +
2.2.ION K+
2.2.1. Vi acid perclorid HClO4: K+to ra kt ta perclorat mu trng.
K+ + HClO4 KClO4 + K+
2.2.2. Vi acid tatric H2C4H4O6: Trong mi trng trung tnh hay acetic
(pH=5-7), K+cho kt ta trng.
K++ H2C4H4O6 KHC4H4O6 + H+
2.2.3. Vi thuc thacid picric:K+
cho kt ta mu vng.Phn ng nhum mu ngn la: t cc mui K+trn ngn la khng mu th
ngn la sc mu tm.
2.3.ION Na+
2.3.1. Vi thuc thKontop (km uranyl acetat): trong mi trng trung
tnh hay acid acetic, Na+cho ta vng vi Kontop.
OHCOOCHCOOCHUOZnNa 238332 9)()( OHCOOCHUOZnNa 29332 9,)()(
Tinh thvng, hnh mt nhn khi soi di knh hin vi.
2.3.2. Phn ng nhum mu ngn la: t cc mui natri trn ngn la
khng mu th ngn la sc mu vng. Phn ng rt nhy nn phi ra dy
OHg
Hg
NH2I
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bch kim tht sch trc khi tin hnh phn ng v chkt lun c ion Na+
khi ngn la mu vng tn ti vi giy trln.
CU HI N TP
1.Trnh by tnh cht chung ca cation nhm VI?2. Gai thch nguyn nhn phi xc nh cc cation nhm VI theo thtNH4
+,
K+, Na+?
3. Ktn cng thc ha hc, hin tng c trng ca cc phn ng xc nh
ion NH4+, K+, Na+v vit phng trnh ion minh ha?
4. Hy cho bit s khc nhau c bn gia catio nhm VI v cc cation 5 nhm
u khi tc dng vi thuc thnatri carbonat?
5. Lm th no xc nh cc cation nhm VI thn hp cc cation bt k?
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BI 8
CC PHNG PHP XC NH CC ANION NHM I
MC TIU
1. Trnh by c hin tng c trng ca cc anion nhm I khi tc dng
vi bari nitrat, bc nitrat v vit phng trnh ion minh ha.
2. K c tn, cng thc ha hc, hin tng ctrng ca TT xc nh cc
ion Cl-, Br-, I-, S2-, NO3- v vit phng trnh ion minh ha.
3. Thao tc ng k thut thanion nhm I vi cc TT s b, TT aion v xc
nh anion nhm I.
NI DUNG
Anion nhm I gm c: Cl-, Br-, I-,S2-.
1.
THUC TH S B
Bari nitrat: cc anion nhm I tc dng vi Ba(NO3)2khng cho kt ta v
to ra mui bari tan (BaS2, BaCl2,)Bc nitrat:
Cc ion Cl-, Br-, I-,S2- to ra cc ta mu, cc ta ny khng tan trong
HNO32N.
Cl-+ AgNO3 = NO3- + AgCl (trng)
Br- + AgNO3 = NO3- + AgBr (vng nht)
I- + AgNO3 = NO3- + AgI (vng nht)
S2-+ AgNO3 = NO3- + Ag2S (en)
2.
THUC TH XC NH ANION
Phn ng chung xc nh X-:
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Dng cht oxy ha mnh l KMnO4 trong mi trng acid sulfuric oxy
ha X-thnh halogen tdo (X2) ri nhn bit cc halogen bng thuc th c
hiu.
Phng trnh phn ng:10X-+ 2KMnO4+ 8H2SO4= 2MnSO4+ K2SO4+ 5X2+ 5SO4
2-+ 8H2O
i vi Clo (Cl2): dng thuc thl giy tm Vilier-Fayol giy chuyn thnh
mu xanh tm.
i vi Brom (Br2): dng thuc th l giy tm fluoressein, giy chuyn t
mu vng sang hng.
i vi iod (I2): dng thuc th l giy tm h tinh bt giy chuyn thnh
mu tm xanh.
Cc thuc thring ca ion Cl-, Br-, I-:
Thuc th ca Cl- l AgNO3: ion Cl- tc dng vi AgNO3 to ta trng tan
trong NH4OH.
Thuc th ca Br- l nc clor: ion Br- b nc clor oxy ha thnh brom.
Brom ha tan trong cloroform lm cho lp cloroform c mu vng nu.
Cl2+ 2Br- = 2Cl-+ Br
2
Thuc thca I-:
Thy ngn clorid: ion I- tc dng vi HgCl2 to ra kt ta , ta ny tan
trong dung dch I-d.
HgCl2+ 2I- = HgI2 + 2Cl
-
HgI2+2I- = [HgI4]
2-
Ch acetate: ion I-tc dng vi Pb(CH3COO)2to ra kt ta vng ti.
Pb2++2I- = PbI2Thuc thca ion S2-:
Ch acetate:to kt ta en.
Pb2++2S2- = PbS
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Acid v c mnh:ion S2-b cc acid v c mnh (HCl,H2SO4) phn hy to
thnh kh hydro sulfur c mi hi.
S2-+ 2H+ = H2S
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BI 9
CC PHNG PHP XC NH ANION NHM II
(AsO43-, AsO3
3-, PO43-, BO3
2-, HCO3-, CO3
2-)
MC TIU
1. Trnh by c hin tng c trng khi anion nhm II tc dng vi TT s
bv vit phng trnh ion minh ha.
2. Trnh by c phn ng chung xc nh AsO43-, AsO3
3v HCO3-, CO3
2-
v vit phng trnh ion minh ha
3. K c tn, cng thc ha hc, hin tng c trng ca TT phn bitHCO3
- v CO32-, TT ca ion PO4
3-v vit phng trnh ion minh ha
4. Thao tc ng k thut thanion nhm II vi cc TT v xc nh anion
nhm I, II.
NI DUNG
1.
THUC TH S B
Bari nitrat: cc anion nhm II tc dng vi Bari nitrat u cho ta trng, cc
ta ny tan trong HNO32N, v chng l mui ca cc acid yu nn b acidnitric phn hy.
BO2-+ Ba2+ Ba(BO2)2
AsO43-+ 3Ba2+ Ba3(AsO4)2
2AsO33-+ 3Ba2+ Ba3(AsO3)2
2PO43-+ 3Ba2+ Ba3(PO4)2
CO32-+ Ba2+ BaCO3
Ring ion HCO3- khng to c kt ta vi Ba(NO3)2 nhng b phn tch
thnh CO32-, nn cc dung dch ion HCO3
-cho ta trng vi Ba(NO3)2
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Bc nitrat:cc ion nhm II tc dng vi AgNO3u cho kt ta, cc ta ny
tan trong HNO3.
3AgNO3+ AsO33- Ag3AsO3+ 3NO3
-
(vng)
3AgNO3+ AsO43- Ag3AsO4+ 3NO3
-
(nu)
3AgNO3+ PO43- Ag3PO4 + 3NO3
-
(vng)
AgNO3+ HCO3- AgHCO3 + NO3
-
(trng)
2AgNO3+ 2CO32- Ag2CO3+ 2NO3
-
(trng)
Ta Ag2CO3lu bphn tch thnh Ag2O c mu xm.
2.
THUC THANION
2.1. Phn ng chung xc nh AsO43- v AsO3
3-:dng hydrogen mi sinh
(do Zn + H2SO42N) khAsO43-, AsO3
3- thnh kh hydroarsenid (AsH3),
kh AsH3bay ln gp giy tm AgNO3lm cho giy c mu en.Zn + H2SO4 ZnSO4+ 2H
0
3H++ AsO33-+ 6H0 AsH3 + 3H2O
3H++ AsO43-+ 8H0 AsH3 + 4H2O
Phn bit AsO33-v AsO4
3-phi da vo phn ng vi AgNO3
2.2.Phn ng ring ca ion AsO43-:ion AsO4
3-tc dng vi hn hp MgCl2
+ NH4Cl + NH4OH to ra mui kp MgNH4AsO4kt ta trng.
AsO43-+ Mg2++ NH4+ MgNH4AsO4
2.3.Thuc thchung ca HCO3-v CO3
2-:
2.3.1. Thy ngn (II) nitrat:ion HCO3-v CO3
2-tc dng vi Hg(NO3)2to
ra kt ta nu hay vng nu.
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2.3.2. Acid v c mnh hay acid acetic: ion HCO3- v CO3
2- b cc acid
mnh nh HCl, H2SO4hoc acid acetic phn hy thnh kh CO2. Kh CO2lm
c nc vi trong.
HCO3-+ H+ CO2 + H2O
CO32-+ 2H+ CO2 + H2O
CO2+ Ca(OH)2 CaCO3+ H2O
2.4.Thuc thphn bit HCO3-v CO3
2-
Dng magnesi chlorid hoc magnesi sulfat:
Ion HCO3-tc dng vi MgCl2cho ta trng
Mg2++ CO32- MgCO3
2.5.Thuc thca ion PO43-
2.5.1.Amoni molybdat:trong mi trng acid nitric, ion PO43-tc dng vi
[(NH4)2MoO4] to ra kt ta mu vng.
Ion AsO33-bHNO3oxy ha thnh AsO4
3-v tc dng vi (NH4)2MoO4tng
t nh PO43-. trnh nhm ln gia AsO3
3-vi PO43-cn xc nh AsO3
3-,
PO43-sau.
2.5.2.Hn hp MgCl2+ NH4Cl + NH4OH:ion PO43-
tc dng vi hn hpMgCl2+ NH4Cl + NH4OH to ra mui kp MgNH4PO4kt ta trng.
PO43-+ Mg2++ NH4
+ MgNH4PO4
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BI 10
CC PHNG PHP XC NH ANION NHM III
NO3-, C2O4
2-
Mui nitrat thrn khi t nng l mt cht oxy ha rt mnh v dbphn
hy. Dung dch nitrat trong nc khng c kh nng oxy ha.
1.
ION NITRAT
Phn ng vi FeSO4NO3
-l cht oxy ha mnh, khi tc dng vi FeSO4trong mi trng H2SO4,
NO3-bkh n oxyt nit, cht ny to vi FeSO4d thnh phc cht sulfat
nitrozil c mu nu xut hin ranh gii tip xc gia H2SO4 m c v
nc.
6FeSO4+ 2NO3-+ H2SO4 3Fe2(SO4)3+ 2NO + 4H2O
NO + FeSO4d [Fe(NO)]SO4
Phc khng bn, b phn hy khi b lc hay un. Tin hnh phn ng khingui.
Phn ng vi Al nguyn t
Nhm l cht khmnh, trong mi trng kim Al bkhNO3-thnh NH3.
Kh NH3bay ra lm xanh giy qu .
NO3-+ 3Al + 3 OH- NH3 + 3 AlO2
-
Diphenylamin (C6H5)2NH
Trong mi trng H2SO4m c, ion NO3-tc dng vi diphenylamin to ra
hp cht mu xanh l.
Thuc thGriess:
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Ion NO3- b hydro mi sinh(do Zn + CH3COOH) kh thnh NO2
- (hoc
HNO2) sau acid nitro(HNO2) tc dng vi TT Griess A v Griess B to ra
hp cht azoic c mu hng.
2.
ION OXALATPhn ng vi KmnO4/ H2SO4. Ion C2O4
2-trong mi trng H2SO4khMn7+
thnh Mn2+lm mt mu thuc tm v phng thch kh CO2.
5C2O42-+ 2KMnO4+ 16H
+ 10CO2+ 2Mn2++ 8H2O
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BI 11
XC NH CATION V ANION
TRONG DUNG DCH MUI V C
MC TIU HC TP
1. Trnh by c trnh t xc nh cation v anion trong DD mui v c
2. Thao tc ng kthut xc nh cation v anion trong mt DD mui v c.
NI DUNG
1. Cc th nghim s b
1.1. Xc nh c tnh ca mu
Mu phn tch c thcc dng: Rn: Ha tan vi cc dung mi thch hp ri mi phn tch.
Dung dch trong sut: phn tch trc tip
1.2. Quan st mu ca dung dch:c th gip d on mt s ion.
V d:
Xanh lam c Cu2+
Hng c Co2+
Vng c Fe3+,I-
Xanh ru c Cr3+
1.3. Ngi mi ca dung dch
Mi gim CH3COOH
Mi khai NH3
1.4. Th pH dung dch: dng giy qu th pH.
1.4.1. pH trung tnhKhng c ion dbthu phn nh Bi3+,Hg2+,...
1.4.2. pH acid
Khng c ion db phn hu mi trng acid: CO32-,...
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Khng c cc cp oxy ha- khc thphn ng vi nhau nh: MnO4-
vi I-, Fe3+vi I-,...
1.4.3. pH kim
Khng c cc ion dbta mi trng kim: Bi3+, Ca2+, Ba2+C th c cc ion lng tnh: Pb2+, Al3+, Zn2+
1.5. Cc phn ng nhn din s b
1.5.1. Cc ion to hydroxyd t tan
DD + NaOH 3M tng git. Kt ta c mu
Rst Fe3+
Trng ha mu c Mn2+
Xanh Cu2+
1.5.2. Cc ion c tnh oxy ha hay kh
1 git DD + 1git HCl + 1 git KI dd nu c thc ion c tnh oxy
ha
1 git DD + 1 git KMnO4long + 1 git HNO3 mu tm mt c
thc ion c tnh kh.
2. Trnh t xc nh cation v anion trong dung dch mui v cTrong dung dch mui tinh khit bao gicng cha mt cation v mt anion
gc acid.
V d: dung dch mui ZnSO4c cha cation Zn2+v anion SO4
2-.
Khi xc nh mui v c trong DD ngi ta tin hnh xc nh cation v
anion ri suy ra mui cn tm.
Vic xc nh cation v anion tin hnh c lp vi nhau, tuy nhin c mt s
cation gy tr ngi cho vic xc nh anion v ngc li. khc phc tr
ngi trn v trnh nhm ln cn tin hnh xc nh cation v anion theo mt
trnh tsau
2.1. Quan st dung dch gc
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NU DD gc c mu th xc nh cation c mu tng ng trc, xc nh
anion sau
Nu DD gc khng c mu th tin hnh th s b.
2.2. Thm u vi NatricarbonatNu DD gc + Na2CO3khng c ta, xc nh anion trc, xc nh cation
nhm VI ( NH4+, K+, Na+) sau.
Nu DD gc + Na2CO3c ta( trng, mu) xc nh cation 5 nhm u trc
(theo s tng qut xc nh cation, xc nh anion sau).
Ch :
Bit c anion, c thgip loi trmt scation:
C I-,Br-,Cl-khng c Ag+
C SO42- khng c Ba2+, Sr2+,Pb2+
Phn tch theo hthng da vo cc nhm thuc th
Ring mt sCation c thtm ngay tdung dch u: Zn2+, Fe3+,Bi3+,...
CU HI N TP
1. Trnh by trnh t xc nh cation v anion trong DD mui v c?2. Hy v s xc nh cation v s xc nh anion?
3. Vic nh hng tm cation v anion trong bng sau ng hay sai?
Hin tng nh hng S
DD gc + Na2CO3c ta en.
DD gc + Na2CO3 khng c
ta.
DD gc + Na2CO3c ta trng
+ cht bay hi.
Tm cation t nhm I n V trc,
tm anion sau
Tm cation trc, tm anion
sau.Tm ion Bi3+ trc, tm anion sau
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4. Hy m tli qu trnh tin hnh v vit phng trnh ion minh ha, khi
xc nh c DD gc l BaCl2?
5. Yu cu thmt l ha cht (th rn) c dn nhn Magnesi clorid tinh
khit th phi lm thno?6. Hy sdng bng kim c khng tkim tra trnh t thao tc k
thut xc nh cation v anion?
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NI QUY PHNG THC TP
LIN BMN HA PHN TCH- KIM NGHIM-C CHT
1. Mi tiu nhm thc tp gm 3 sinh vin ( nhm trng tchia 12 tiu
nhm & gi danh sch vcho Cn BPhc VGing Dy) lm chung
mt bi v chu trch nhim vbi ny trn mi phng din: trt t, kt
qu, dng c.
2. Sinh vin phi c mt ti phng th nghim trong sut bui thc tp. Sinh
vin n trqu 15 pht mt ln bkvng mt mt bui.
3. Sinh vin vng mt qu mt bui thc tp m khng c xin php vi l dochnh ng s khng c thi thc tp cui kha.
4. Nu ngh c l do chnh ng, sinh vin phi lm n xin php km giy
t xc minh l do v phi xin hc b vo bui khc vi Cn BGing
Dy.
5. u mi bui, 1 sinh vin i din nhm mnh k nhn mn dng c.
Cui bui, dng cphi c ra sch s, kim tra, k nhn trcho Cn
BPhc VGing Dy. Tiu nhm thc tp phi chu trch nhim vs
mt mt, h bdng cca tiu nhm.
6. Sinh vin phi mc o chong trng, mang bng tn khi thc tp.
7. Tuyt i cm ht thuc trong phng th nghim.
8. Khng c ci ni n o, n ung hoc lm vic ring trong khi thc
tp.
9. Khng c ngi trn bn thc tp.
10.Cui mi bui thc tp nhm trng phn cng cc tiu nhm thay nhau
vsinh phng th nghim.
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11.Trc khi vo phng thc tp, sinh vin phi c kbi l thuyt v thc
hnh ca bi thc tp.
12.Mi tiu nhm np mt bi bo co (theo mu) vo u mi bui thc tp
ca bi ktip ng 7h, 13h & 18h, sau thi im ny khng nhn & ctiu nhm phi nhn 0 im cho bi bo co .
13.im thi mi mn thc tp l 10 im.
14.Cc mn iu kin: Ha phn tch nh tnh v Ha phn tch nh lng.
Sinh vin thi thc tp 02 mn ktrn phi t im nm (5) trln mi
iu kin thi l thuyt. Ring Kim nghim thuc l mn chuyn
ngnh, im thi thc tp & l thuyt tnh c lp. Thi l thuyt gm cc
hnh thc: trc nghim MCQ, in khuyt.
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S CU TRONG PHNG TH NGHIM
Khi acid c (acid sulfuric, acid nitric,) ri ln da ph i ra ngay ch
bbng bng tia nc mnh trong vng 3 5 pht, sau dng bng tn dung
dch tannin trong ru hoc dung dch kali permanganat 3% bi nh ln vt
bng. Nu bbng bi kim c th tin hnh cu cha bc u nh trn
nhng ra bng dung dch acid acetic 2%.
Khi bacid hoc kim c bn vo mt, phi ra mt bng nhiu nc,
sau phi n ngay bnh vin.
Khi bbng bi cc vt nng (thy tinh, kim loi,) th u tin phi
bi dung dch tannin trong ru hoc dung dch KMnO43% ri bi mchng
bng. Khi bbng bng phospho cn bi chbbng bng dung dch ng
sulfat 2%.
Khi b ng c clor, brom, hydro sulfur, cacbon oxid cn a ngay
ngi bnn ra chkhng kh trong lnh.
Nu b ng c bi cc cht arsen, thy ngn cng nh cc muicyanua cn phi nhanh chng a ngi bnn n bc s.
Khi b t tay do dao hay mnh thy tinh cn lau sch mu, bi thuc
st trng (cn hay dung dch KMnO4long), sau cm mu bng dung dch
FeCl3 ri bng li.
Khi qun o ang mt trn ngi bchy mt din tch ln th tuyt i
khng c chy hoc ra chgi, phi nm xung t m ln, trng hp
chy trn din tch b th dng gi lau, dng nc hoc bt kmt phngtin no thch hp dp tt chchy, tuyt i khng c dng bnh cha
chy (thng l cha CO2) phun vo ngi ang bchy qun o, m phi
dng nc di hay trm kn bng chn.
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CCH S DNG DNG C, THUC TH
V MT S THAO TC C BN
1. DNG C
1.1. ng nghim
Ra v trng
v bha cht, trng bng nc my.
Cbng chi ui chn, ra bng nc my, trng li bng nc ct.
unDng kp ghay kp kim loi, cm phn cn di.
Thtch dung dch khng c qu ng nghim.
un mt thong ca lp dung dch trn ngn la, va un va lc, lun lun
phi hng ng nghim vpha khng c ngi.
un xong, trnh t ng nghim ang nng vo ni m t.
1.2. Pipet
Trc khi dng phi ra sch bng nc my, trng li bng nc ct.Mi pipet chdng mt loi thuc th.
Dng khn hay gi sch thm git thuc th d ng u pipet, khng c
vy xung nn gch.
1.3. n cn
Khng c nghing n t, phi dng giy mi, giy cn chy khng
c vt vo st rc.
Dng chp nha tt ngn la, khng c thi.
Nu cn cn m n t khng chy, phi ly tim n ra vt ht nc ri lp
li v t.
1.4. Ni cch thy
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Mc nc bn ngoi lun bng hay cao hn mc nc trong ng nghim
Nn nh shay lm du ring trnh nhm ln.
1.5. My ly tm
Dung dch cha trong ng nghim khng c qua t thtch.Lun phi c 2 ng t i xng nhau trn my v cha nhng lng dung
dch tng ng.
y np trc khi my chy, chmnp khi my ngng hn.
Phi nh du ng nghim trnh nhm ln.
2. THUC TH
Thng sp xp thnh 2 loi:
2.1. Thuc thtrong hp g
Gm cc loi thng thng nh acid, base long, mt smui.
2.2. Thuc thtrn k
cc acid v base m c, thuc th c hiu, thuc thnhm.
c ktn, cng thc ha hc, nng trc khi dng.
i vi cc acid, base m c (NH4OH, HNO3, HCl,...) phi y np sau khi
ly.
Dng pipet ring cho mi loi thuc th.
3. MT S THAO TC C BN
3.1. Cch dng giy chththpH
C 2 loi: quxanh v qu xanh. Cho 1 mu nh, di khong
0.5 cm, t ln chsch kh. Dng a khuy nhng vo dung dch cn xc
nh pH, chm mt git dung dch ln giy, quan st s i mu.
3.2. Lm phn ng kt taLy khong 1 ml (20 git) dung dch cn thnghim cho vo ng nghim ri:
Thm tng git thuc th,va thm va lc (nu l ta tinh th)
Thm ttcho ht lng thuc thch nh ri lc (nu l ta v nh hnh).
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Mun ta hon ton th sau khi cho thuc th ta phi lc k, ly tm ri
thm mt git thuc ththeo thnh ng nghim vo lp nc trong pha trn.
Nu cn c ta l thuc th cha , phi thm tip vi git thuc th, ly tm
v thli n khi khng cn ta na.
3.3. Tch ring ta v dung dch
Sau khi ly tm, lc qua giy lc hoc cn thn gn dung dch bn trn qua ng
nghim khc, trnh lm xao ng dung dch v nu khng smt ta.
3.4. Ra v ha tan ta
Cho mt t nc ct (khong 1ml), vo ng nghim, lc mnh, nu cn th ly
tm ri b nc ra hay nhp vo dung dch tch ta. Lp li nh th 2 n
3 ln.
Sau khi ra sch, ta c ho tan hon ton bng cch thm tng git
dung mi thch hp (nc, acid, base ...). Lc u sau mi ln thm. un nh
hay un si tu theo yu cu ca tng cht cho n khi ta tan hon ton.
Trnh cho d nhiu acid hay base v scn trcc phn ng sau.
3.5. Quan st mu dung dch hay ta
Cc phn ng to phc thng cho ra nhng phc mu tan hay khng tan, khi
thc hin phi ch n pH ca dung dch.
Quan st mu: nhn trn nn trng.
Quan st skhng mu hay dung dch c t ta: nhn trn nn en.
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BI 1
XC NH CC CATIONNHM I (Ag+, Pb2+, Hg22+)
1.
DNG C - HA CHT THUC TH
Dng c
n cn
a thy tinh
ng nghim cc loi
ng nghim ly tm
My ly tm
Ha cht, thuc th
1. K2CrO40,5 M
2. KI 0,5M
3. HCl 6M
4.NH4OH
5.NaOH 6M
6. H2SO43M
7. HNO3
8. Dy ng
9. HNO33M
2.
THC HNH
2.1. Tm Ag+
2.1.1. Vi HClAg+ + Cl-AgCltan / NH4OH m c [Ag(NH3)2]Cl
Ly 5 git Ag+ + 1 git HCl 6M trng vn. Ly tm ly ta, thm
NH4OH m c tha tan (do to thnh [Ag(NH3)2]+). Acid ha li
bng HNO3m c trli.
2.1.2. Vi KI
Ag+ + I- AgI (ta ng vng)
Ly 5 git Ag+ + 2 git I-ta ngvng.
2.2.
Tm Pb2+
2.2.1. Vi HCl
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Pb2+ + Cl- PbCl2 (trng hnh kim, tan / nc nng)
Ly 5 git Pb2++ 1git HCl 6Mtrng. Ly tm ly ta, thm 20 git
nc ct un nng tan.
2.2.2. Vi KI
Pb2++ I- PbI2(ta vng tan/ nc nng)
Ly 5 git Pb2++ 1 git I- ta vng. Ly tm ly ta. Thm 10 git
nc ct. un nng tan. Lm lnh t ngt ta hnh vy mu vng
ng nh.
2.2.3. Vi K2CrO4
Pb2+
+ CrO4PbCrO4vng, tan trong NaOH 6MLy 5 git Pb2++ 1 git K2CrO4vng. Thm NaOH 6M tha
tan.
2.2.4. Vi H2SO4
Pb2++ SO42-PbSO4trng
Ly 5 git Pb2++ 1 git H2SO4trng.
2.3. Tm Hg22+
2.3.1. Vi HCl
Hg22++ Cl- Hg2Cl2trng vn (Calomel)
Hg22+ Hg0+ HgNH2Cl en xm
Ly 10 git Hg22++ 1 git HCl 6M trng. Ly tm ly ta, thm
vi git NH4OH m c en xm.
Hg2Cl2+ 2NH4OH HgNH2Cl + Hg0 + NH4Cl + 2H2O
2.3.2. Vi dy ngHg2
2++ Cu0Cu2++ Hg0en
Nhng dy ng vo dung dch Hg22+dy Cu b en. H nng dy
ng li sng (Hg thng hoa).
NH4OH
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3.
S PHN TCH MT VI CATION NHM I
AgCl, PbCl2 , Hg2Cl2 II...VI
PbI2vng
Pb2+Cl- AgCl, Hg2Cl
2
PbCrO4 vng Hg ,HgNH2Cl [Ag(NH3)2]+
AgCl
(Ag+)
HNO3H+
trng
en xm
(Hg22+
)
Dung dch u
+ HNO33M H+
+ HCl 6M n ta hon ton. Ly tm
Ra ta (1ml ED + 2 HCl 6M)10 git ED. un nng. Ly tm
Chia 2 NH4OH . Lc klytm
1 git KI 1git K2CrO4
Ta Dch
(Pb2+
)
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Bi 2
XC NH CATION NHM II(Ba2+, Ca2+)
1.
PHN NG NH TNH CA ION Ba2+
1.1. Vi tc nhn c SO42-: H2SO4, (NH4)2SO4,..
Ba2+ + SO42-trng
Ly 5 git Ba2++ 2 git H2SO4 3M ta trng
1.2. Phn ng Voller
Ly 5 git Ba2+, thm 1 git thuc thKMnO4, thm 5 git H2SO4 3M,
c kt ta, ly tm, sau thm H2O2 t t tng git n khi dung dch mtmu hng tm cn kt ta c mu hng.
1.3. Vi (NH4)2CO3
Ba2++CO32-BaCO3tan trong CH3COOH 6M, axit v c
Ly 5 git Ba2++ 1git CO32-trng. Thm CH3COOH 6M tha
tan.
1.4. K2CrO4
Ba2+ + CrO42-BaCrO4vng, khng tan trong CH3COOH
6M, thm CH3COOH 6M tha vn khng tan
1.5. (NH4)2C2O4
Ba2++C2O42-Ba2C2O4trng
Ly 5 git Ba2++ 2git C2O42-trng.
2.
PHN NG NH TNH CA ION Ca2+
2.1. Vi H2SO4
Ca2++ SO42-CaSO4(chta khi [Ca
2+] kh c hay c cn 960)
Ly 10 git Ca2++ 2 git SO42-+ 5 git C2H5OH 96
0trng
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2.2. Vi NH4)2CO3:thc hin tng t nh Ba2+
2.3. Vi (NH4)2C2O4
Ca2++C2O42-CaC2O4trng, khng tan trong CH3COOH
Ly 5 git Ca2++ 2 git (NH4)2C2O4+ 1git NH4OH . un nh
trng
3. S PHN TCH CATION NHM II
Dung dch uDung dch u
NH4OH OH-
Na2CO3bo ho n ta hon tonun nng. Ly tm. Bdd.Ra ta.Ho ta li bng CH3COOH 6M.
+ (H2O +H2SO43M + cn 900 ).
+ Na2CO3bo ho, dun si kgnB nc. Lm 3 ln
Ra ta 2 ln, bng ncCH3COOH 6M (ha tan)K2CrO4cho d n ta hon ton.
III ... VI
( Ba2+)
(vng)
NaOH 3Mlc k
(NH4)2SO450% ng lngCT 15 pht. Ly tm
NH4OH trung tnh1 git NH4OH10 git (NH4)2C2O4BM (15). Ly tm
PbO22-
BaSO4, CaSO4,(PbSO4)
BaCO3, CaCO3,(PbCO3)
Trng
dd Ca2+,CrO42-PbCrO4,BaCrO4
CaC2O4
dd Ca2+
dd Ca2+BaCrO4
+ H2SO43M n ta hon tonun nng, ngui, thm 1/2 thtch cn 90o+ H2SO43M n ta hon tonun nng, ngui, thm 1/2 thtch cn 90o
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Bi 3
XC NH CATION NHM III (Al3+, Zn2+)
1.
PHN NG NH TNH CA ION Al3+
1.1. Vi NH4OH, NaOH
Al3++ 3OH-Al(OH)3bng trng + OH- AlO2
-+ 2H2O
AlO2-+NH4
+ + 2H2O Al(OH)3 + NH4OH
Ly 5 git Al3+ + 1 git NaOH 3M bng trng xut hin. Thm
NaOH 3M tha, ta tan, tip tc thm bt NH4Cl, un nng, ta xut hin tr
li.Ch : mun thy ta ca Al(OH)3 ta phi thm NaOH t t theo thnh
ng nghim, v ta ny tan rt nhanh trong mi trng NaOH.
1.2. Vi thuc th aluminon
Al3++ Aluminon Ta bng , khng bphn hy
bi NH4OH v (NH4)2CO3
Ly 5 git Al3++ 5 git Aluminon + 10 git m acetat. un nng thm
NH4OH 2N ti khi c mi NH3ri cho 2 3 git (NH4)2CO3bng
Ion cn tr: Fe3+, Cr3+, Ca2+, Cu2+, Bi3+,...
2. PHN NG NH TNH CA ION Zn2+
2.1.Vi NH4OH
Zn2++ 2OH-Zn(OH)2 [Zn(NH3)4]2++ H2O
Ly 5 git Zn2++3 git NH4OH 3M trng. Thm NH4OH d
tan.
2.2. Vi NaOH
Zn2++ 2OH-Zn(OH)2 ZnO22-(Zincat) + 2H2O
t0
CH3COO-/CH3COOH
+ NH4OH d
NaOH
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Ly 5 git Zn2++ 2 git NaOH 3M Zn(OH)2trng. Thm NaOH
6M d tan.
2.3.Vi thuc th M.T.A:(NH4)2[Hg(SCN)4] (Mercuri Thiocyanat Amoni)
Zn2++ Cu2++2[Hg(SCN)4]2- ZnCu[Hg(SCN)4]2
Ly 10 git Zn2++ 1 git Cu2++ 2 git M.T.A tm sim
Ch :mi trng trung tnh, lng Cu2+phi t , nu tha Cu2+, kt ta
s tm en.
III. PHN TCH CATION NHM III
Dung dch c cc cation III,IV,V
Ta nhm IV,V AlO2 ,ZnO22-
Al(OH)3 [Zn(NH3)4]2+
Al3+
bng
(Al3+
)
Zn2+PbCrO4vng(Cr3)
tm xim
(Zn2+
)
CH3COOH 6MH+
Pb(CH3COOH)2
* Cu2+
* MTA
NaOH 3M d + vi git H2O2un k n ht bt.
un siNH4Cl bo ha 5gitun kvi git
NH4OH . Ly tm
Ho tan bng HNO33M
Aluminonm acetatun nh
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BI 4
CC PHNG PHP XC NH CATION NHM IV
Fe3+, Mn2+, Mg2+ & Bi3+
THUC THNHM: NaOH 3M,& H2O2
1.
PHN NG NH TNH
1.1.
ION Fe3+
1.1.1. Vi NH4OH
Fe3++ 3OH Fe(OH)3 nu .
Ly 5 git Fe3+ + 1 git NH4OH nu .
1.1.2.
Vi Kaliferrocyanid K4[Fe(CN)6]
4Fe3++ 3[Fe(CN)6]4- Fe4[Fe(CN)6]3 xanh ph.
Ly 5 git Fe3++ 1 git K4[Fe(CN)6] xanh ph.
1.1.3.
Vi thuc thKSCNFe3++ 3SCN- Fe(SCN)3 mu.
Ly 5 git Fe3++ 1 git KSCN dung dch mu.
1.2. ION Mn2+
1.1.1.
Vi NaOH
Mn2+ phn ng vi NaOH cho ta trng Mn(OH)2. lu ngoi khng kh
hoc khi c shin din ca H2O2schuyn thnh mu nu MnO2.
Mn2++ NaOH + H2O2 MnO210 git Mn2++ 3 git NaOH v thm 5 git H2O2 ta nu,...
1.1.2.
Phn ng oxy ha
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Vi tc nhn oxy ha mnh nh PbO2/HNO3, Mn2+boxy ha thnh Mn7+c
mu tm.
Ly 10 git Mn2++ mt t bt PbO2+ 5 git HNO3 un nng
dung dch c mu tm.Ch : trong dung dch tm Mn2+phi khng c c cc ion mang tnh kh
nh Cl-, Br-, I-. Nu c phi loi trc bng AgNO3.
1.3. ION Mg2+
1.1.1.
Vi NaOH, NH4OH
Mg2++ 2OH- Mg(OH)2 ta trng.
1.1.2.
Vi Na2HPO4/NH4Cl- NH4OH
NH4OH/ NH4Cl
Mg2++ Na2HPO4 ta trng hnh sao hay hnh l
tan trong acid. (Nu khng c NH4OH NH4Cl ta dng v nh hnh).
Ly 10 git Mg2++ 2 git NH4Cl + NH4OH OH- + 3 git Na2PO4
ta trng.
1.1.3.
Vi thuc thvng Thiazol
Mg2++ vng Thiazol + NaOH ta nh tm.
Ly 10 git Mg2++ 1 git vng Thiazol + NaOH 6M OH-, lc
nh. Quan st ta trn thnh ng nghim c mu nh tm.
1.4.
ION Bi3+
1.1.1.
Phn ng thy gii: (pH trung tnh hay hi acid)
Bi3++ Cl-+ H2O + 2H++ BiOCl trng tan trong acid mnh.
Ly 5ml nc ct + 1 git NH4Cl + 1 git Bi3+ trng
1.1.2. Phn ng Stanit kim (SnCl2/NaOH)
2Bi3++ 3SnO22-+ 6OH- 2Bi + 3SnO3
2- + 3H2O
Ly 3 git SnCl2+ 10 git NaOH 3M. Lm lnh + 1 git Bi3+ en.
1.1.3.
Vi Thioure
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Bi3++ 2SC(NH2)2 + 3A- [Bi(NH2-CS-NH2)3]
3+ +3A-
Ly 5 git Bi(NO3)3 + mt t bt Thioure dung dch vng.
II. PHN TCH CATION
Nhm IV, V Nhm III
HNO3Nhm IV, V
Nhm VHydroxyt nhm IV
Na2CO3thong cNH4OH d
NH4Cl bo ha
Dung dch u III, IV, V
TmMn2+ Ta en Bi3+ muFe3+
PbO2HNO3un nng
SnCl2NaOH KSCN
Fe3+, Mn2+, Bi3+ nh tm Mn2+
NaOHThiazol
Fe(OH)3, MnO2, Bi(OH)3 Mn2+
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BI 5
CC PHNG PHP XC NH CATION NHM V
I. CC PHN NG NH TNH
1.Tm Cu2+
1.1. NH4OH
Cu2+ + NH4OH long Cu(OH)2 NH4OH d
[Cu(NH3)4]2+
Ly 5 git Cu2++ 2 git NH4OH 3M ta xanh Thm NH4OH va
d dd xanh da tri.
1.2. M.T.A (Mercuri Thiocyanat Amoni)Cu2++ Zn2++ ( NH4)2[Hg(SCN)4]2 CuZn[Hg(SCN)4]2tm sim
Ly 1 git Cu2++ 5 git Zn2++ 2git MTA tm sim.
1.3. Na2S2O3
2Cu2++3S2O32-+ H+ Cu2S + S4O6
2-+H2O
Ly 5 git Cu2++ 3 git Na2 S2O3+HCl 3M un nng en
2. Tm Hg2+
2.1. Vi NH4OH
HgCl2 NH2HgCl trng NH4OH d
[Hg(NH3)4]2+
Ly 5 git HgCl2+ 3 git NH4OH 3M trng. Thm NH4OH d
tan
2.2. SnCl2
SnCl2 + 2 HgCl2SnCl4 + Hg2Cl2trng Hg0
enLy 5 git SnCl2 + 5 git HgCl2en xm
2.3. KI
Hg2++ 2I-HgI2cam + 2I- [HgI4]
2-khng mu
un
NH4OH
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Ly 10 git Hg2++ 1 git KI theo thnh ng nghim . Thm KI d
tan.
Cc cation nhm V trc tiptdung dch u:c thtm trc tip tdung
dch u: Cu2+, Hg2+.
Tm Cu2+: 1 git DD + 5 git km + M.T.Atm sim.
Hg2+ : dng thuc thSnCl2 en xm, hoc dng TT KI to kt
ta cam thm d KI ta tan y l phn ng phn bit vi Hg22+
.
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BI 6
XC NH CATION NHM VI (NH4+, K+, Na+)
KHNG C THUC THNHM
1. PHN NG NH TNH
1.1. ION NH4+
1.1.1.Vi NaOH
NH4+ + OH- NH3 + H2O
Ly 5 git NH4++ NaOH 6M OH-. un nh, bt u ng nghim bng
giy qu thm t bng kh NH3 lm giy qu chuyn sang mu xanh.1.1.2.Thuc thvi Nesstler ( hn hp HgCl2+ KI)
KOHHgIKNH 32 2424 7KI + 2H2O +
Ly 5 git NH4++ 3 git Nesstler + 2 git NaOH 6M nu .
Ch : xc nh NH4+ta thbng chai phn ng v chai phn ng u
dng tnh th mi nh danh chnh xc ion NH4+.
1.2. ION K+
1.2.1.Vi HClO4
K++ HClO4 KClO4 trng
Ly 10 git K++ 5 git HClO4 . Lm lnh trng
1.2.2.Phn ng vi thuc thGarola Na3[Co(NO2)6].
Thuc thGarola gm Garola A: Co(NO3)2, Garola B: NaNO2
2K+ + Na3[Co(NO2)6] K2H+[Co(NO2)6] vng ngh
Ly 10 git K++ 5 git Garola A Co(NO3)2+ mt t NaNO2+ 5 git
CH3COOH lc vng ngh.
mi trng OH-hay H+mnh thuc thbph hy. NH4+cho dung dch
mu vng.
OHg
HgNH
2I
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1.3. ION Na+
1.3.1. Vi thuc thKontop ( km uranyl acetat)
OHCOOCHCOOCHUOZnNa 238332 9)()( OHCOOCHUOZnNa 29332 9,)()(
Tinh th vng, hnh mt nhn.
10 git Na++ CH3COOH 6M H++ 10 git thuc th Kontop. un si lm
lnh di vi nc, yn 10 pht, thnh thong dng a thy tinh cvo
thnh ng nghim.
iu kin: mi thng trung tnh hay hi acid (acid acetic), mi trng aicd
mnh ta tan.
Cc ion NH4+, K+, Ca2+, Sr2+, Ba2+, Al3+, gy trngi.
2. PHN TCH CATION
Cc cation nhm VI tm trc tip tdung dch u.
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S PHN TCH TNG QUT 6 NHM CATION THEO
PHNG PHP ACID BASE
Ly Tm
Ly Tm
Ly Tm
Dung dch phn tch cation
Nhm I: (ta clorid)AgCl, Hg2Cl2, PbCl2
Nc ly tm +H2SO42N
Nhm IV: (dung dchphn tch): NH4
+, Na+, K+
Nhm II: (ta sulfat)BaSO4, CaSO4, (SrSO4)
Nc ly tm+ NaOH 2N d
(+ H2O2)
Nhm III: (nc ly tm cha oxoanion)AlO2
+, ZnO22-, (SnO3
2-, CrO42-)
Kt ta(oxyd, hydroxyd nhm(IV + V)
+ HNO3(+ H2O2)
Nhm IV: (ta hydroxyd)Fe(OH)2, Fe(0H)3,
Bi(OH)3, MnO2, Mg(OH)2
Nhm V:(nc ly tm cha phc amino)Cu(NH3)4
2+Hg(NH3)42+,
(Ni(NH3)42+, Co(NH3)6
+,Cd(NH3)42+
Nc ly tm+ Na2CO3ti thong c
+ NH4OH c(+H2O2)
Ta HsbO3(hoc Sb2O5.H2O)Ha tan bng HCL cXc nh Sb:
- Phn ng thy phn- Thu c thCaille-Viel
+ HCL 6NL tm
Sb3+,5+c thxp nhm IV do to tahydroxyd/acid, khng to phc amoniacat/hoc xp ring
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BI 7
XC NH ANION NHM I: Cl-, Br-, I-, S2-, NO3-
THUC THNHM: AgNO3/HNO3
1.
PHN NG NH TNH HALOGENID
1.1. ION Cl-
1.1.1.Vi AgNO3
Ag+ + Cl- AgCl trng vn, tan trong NH4OH, (NH4)2CO3
[Ag(NH3)2]+
Thc hin:5 git Cl-+ 1 git AgNO3 trng. Thm (NH4)2CO3d,
ta tan.
1.1.2. Phn ng oxy ha thnh Cl2
10Cl-+ 2MnO4-+ 16H+ 5 Cl2+ Mn
2++ 8H2O
Kh Cl2bay ln lm xanh giy tm Orto Toludin.
Thc hin:10 git Cl-+ 4 git H2SO4 + 2 git MnO4-. Bt u ng nghim
bng giy tm Orto Toludin, quan st mu xanh tm.
1.2. ION Br-
1.2.1. Vi AgNO3
Ag++ Br- AgBr vng nht
Thc hin:5 git Br-+ 1 git AgNO3 vng nht. Ly tm ly ta. Thm
NH4OH tha ta tan.1.2.2.Phn ng oxy ha thnh Cl2
2 Br-+ Cl2 2Cl-+ Br2(nu) + Cl2 2BrCl vng nht.
t0
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Thc hin:5 git Br-+10 git CHCl3+ nc Cl2bo ha tng git lc u
nu. Thm nc Cl2d vng nht.
1.3. ION I-
1.3.1. Vi AgNO3
I-+ Ag+ AgI vng kem, khng tan trong NH4OH, (NH4)2CO3.
Thc hin:10 git I-+ 1 git AgNO3 vng kem. Chia ta lm 2 ng
nghim. ng (1) thm NH4OH. ng (2) thm (NH4)2CO3lc u.
1.3.2.Phn ng vi nc Cl2
2I-+ Cl2 2Cl-+ I2tm/CHCl3+ Cl2 2ICl khng mu.
Thc hin: 10 git I-+ 10 git CHCl3+ nc Cl2 tng git lp
CHCl3mu tm (sau khi lc u) thm Cl2d mt mu.
2. ION S2-
Pb2++2S2-=PbS
(kt ta en)
Thc hin:5 git dung dch S2-, thm 5 git Pb(NO3)2, c ta en.
III.TM ANION NHM I
2.1.Tm I-
v Br-
Thc hin:10 git dung dch u + 10 git CHCl3+ nc Cl2tng git. Lc
mnh, quan st lp CHCl3
Mu tm, nh thm nc clo mt mu: c I-
Mu vng m + nc clo vng lt: c Br-
Tm vng: c I-v Br-
2.2.Tm Cl-
Nu khng c I-v Br-: lm nh nh tnhTrng hp c I-v Br-: ly 10 git dung dch u + 1 git HNO3+ AgNO3
n ta hon ton. Ly tm ly ta.Thm (NH4)2CO3, un nng. Ly tm ly
dung dch, thm 1 git HNO3nu dung dch c trli c Cl-.
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BI 8
XC NH ANION NHM II
SO42-, BO2-, PO4
3-, CO32-, HCO3
-
THUC THNHM: BaCl2
1.PHN NG NH TNH
1.1. ION SO42-
1.1.1. Phn ng vi BaCl2
Cho ta trng BaSO4. Ta khng tan trong acid v c.
SO42-
+ Ba2+
BaSO4 trngTin hnh:10 git SO4
2-+ 2-3 git BaCl2 ta trng. Thm vi git HNO3
ta khng tan.
1.1.2. Vi Pb(CH3COO)2
Phn ng gia Pb2+vi SO42-cho ta PbSO4khng tan trong HNO3, tan trong
kim.
Tin hnh:10 git SO42-+ 2-3 git Pb(CH3COO)2 ta trng. Thm
vi git HNO3 ta khng tan.
1.2. ION BO2-
1.2.1. Tc dng ca BaCl2
Dung dch borat c tc dng vi BaCl2cho ta trng Ba(BO2)2. ta tan trong
CH3COOH.
BO2-+ BaCl2 Ba(BO2)2
Tin hnh:10 git BO2-+ 3-4 git Ba2+ ta trng. Thm CH3COOH
ta tan.
1.2.2. Vi cn etylic
BO2-phn ng vi C2H5OH cho ete borat etyl (C2H5O)3BO3. Cht ny chy
cho ngn la mu xanh lc.
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BO3-+ 3C2H5OH (C2H5O)3BO3
Tin hnh: ly 20 git dung dch H3BO3, c n cn kh. ngui, thm
1ml H2SO4. Lm ngui, thm 20 git C2H5OH un si, t ming ng nghim
ngn la mu xanh l.
1.3. ION PO43-
Cc mui phosphat tn ti: PO43-, HPO4
2-, H2PO4-.
1.3.1. Phn ng vi BaCl2
HPO42-phn ng vi BaCl2to thnh ta BaHPO4. Ta ny tan trong HCl v
CH3COOH.
HPO42-+ Ba2+ BaHPO4
Tin hnh: 10 git HPO42-+ 3-4 git Ba2+ ta trng
1.3.2.Vi hn hp Mg2+(Mg2+, NH4Cl v NH4OH)
HPO42-cho ta kt tinh trng MgNH4PO4. Ta khng tan trong NH4OH.
HPO42-+ Mg2++ NH4OH + NH4Cl MgNH4PO4
Tin hnh:10 git Mg2+ + 5 git NH4Cl + 5 git HPO42-+ 5 git NH4OH
ta trng.
1.3.3.Vi amoni molypdat (NH4)2MoO4Ion phosphat tc dng vi amoni molypdat trong HNO3 cho ta mu vng
amoniphosphomolypdat.
H3PO4+ 12(NH4)2MoO4+ 21HNO3 (NH4)3PO4.12MoO3.2H2O
Tin hnh:10 git PO43-, un cn bt + 3 git HNO3+ 3 git NH4NO3+ 6
git phosphomolydat, un nh xut hin ta mu vng
1.4. ION HCO3-
1.4.1.Vi acid mnh v c mnh hay acid aceticHCO3
-+ H+ CO2+ H2O
(lm c nc vi trong)
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Tin hnh:nh5 git dung dch ion HCO3-, thm CH3COOH tng git, quan
st ng, thy c kh bay ra.
1.4.2.Vi Hg2+
Hg2++ HCO3- Hg(HCO3)2
(ta nu hoc vng nu)
Tin hnh: nh5 git dung dch ion HCO3-, thm 5 git Hg(NO3)2, c ta
nu hoc vng nu.
1.5. ION CO32-
1.5.1.Vi acid mnh v c mnh hay acid acetic
CO32-+ H+ CO2+ H2O
(lm c nc vi trong)
Tin hnh:nh5 git dung dch ion HCO3-, thm CH3COOH tng git, quan
st ng, thy c kh bay ra.
1.5.2.Vi Hg2+
Hg2++ CO32- Hg(CO3)2
(ta nu hoc vng nu)
Tin hnh: nh5 git dung dch ion HCO3-
, thm 5 git Hg(NO3)2, c ta nu hoc vng nu.
1.5.3. Vi Mg2+
Mg2++ CO32- MgCO3(ta trng)
Tin hnh:nh5 git dung dch ion CO32-,thm 5 git MgCl2,c ta trng.
2. TM ANION NHM II
2.1.Tm SO42-
Tin hnh:10 git dung dch u + 2 git HCl 6M ly tm bta nu
c. Ly dch ly tm + 2 git BaCl2 ta trng c SO42-
2.2. Tm BO2-,PO4
3-:lm nh nh tnh.
2.3. Tm HCO3-v CO3
2-:lm nh nh tnh
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S XC NH ANION NHM I V II
NO3-
Cl-
I-, Br-
Khng kt ta
Dd gc + Ba(NO3)2 Dd gc + AgNO3kt t
a tr
ng
kt ta vng
kt ta en
S2-
kt ta trng
+ HNO32N
tan
Dd gc + AgNO3kt ta nu
kt ta vngAsO43-
AsO33-, PO4
3-
kt ta trng
DD gc + CH3COOHKh
DD gc + Hg(NO3)2 kt ta nu
DD gc+
MgCl2
kt ta trng
Khng kt ta
CO32-
HCO3-
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BI 9
XC NH ANION NHM III (NO3-, C2O4
2-)
1.PHN NG NH TNH
ION NO3-
Phn ng vi FeSO4
Fe(II) kh nitrat n nit oxyd, cht ny to vi mui st d hp phc
[Fe(NO)]SO4lm dung dch nhum mu nu.
NO3-+ Fe2++ H+ NO + Fe3++ 2H2O
NO + FeSO4d [Fe(NO)]SO4Tin hnh: ly 2 ng nghim
ng (1): FeSO4khong ht bp + 10 git H2SO4. ngui.
ng (2): 10 git NO3-+ 5 git H2SO4. Lm lnh.
t tng (2) vo ng (1) theo thnh ng nghim, ni tip gip gia hai
lp cht lng xut hin mt vnh nu.
Phn ng khnitrat bng Al kim loi
Trong mi trng kim Al kim loi khNO3-n amoniac.
2Al3++ NaOH 2NaAlO2+ 2H+
Hydrogen mi sinh khNO3-thnh amoniac
2NO3-+ 18H+ 2NH3+ 6H2O
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Tin hnh: 10 git NO3-+ 5 git NaOH + mt t bt nhm. y ming ng
nghim bng ming giy qu . Kh bay ln lm giy qu c mu xanh.Ch
tm Al3+bng phn ng ny vi iu kin trong dung dch khng c ion NH4+
ION OXALATVi KMnO4/H2SO4
Ion C2O42-lm mt mu ca thuc tm.
5C2O42-+ 2KmnO4+ 16H
+ 10CO2 + 2Mn2++ 8H2O
Tin hnh: 10 git C2O42- + 4 git H2SO4 + tng git KmnO4, un nng
mt mu tm.
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BI 10
PHN TCH HN HP CATION V ANION
TRONG DUNG DCH
1.
Dng cha cht thuc th
C y bdng c, ha cht v thuc thca tt ccc bi phn tch
cation v anion trc .
2.
Thc hnh
Khi nhn c dd hn hp cation v anion cn nh tnh, phi thc hin ln
lt cc bc phn tch sau:
Dng gic quan nhn xt mu sc, mi. a ra d on ban u vcc ionc mt.
Thc hin cc php th s bv:
pH ca dung dch.
Mu ngn la.
T d on tip vcc ion c thc mt.
Thmt sphn ng, c bit l phn ng ca cc thuc th nhm i vi
cation v anion.
Theo , tip tc d on cc ion c thc trong dung dch phn tch.
Tin hnh phn tch h thng hoc na h thng theo cc s thc hnh
phn tch cation v anion.
Sau khi c kt lun vcc cation v anion va tm c tphn tch hthng,
cn i chiu kt lun y vi cc kt qu th s b ban u xem c g mu
thun. Nu cn nghi ngth phi tin hnh phn tch li.