cac-phan-ung-oxi-hoa-khu-thuong-gap-trong chuong trinh pho thong

8/14/2019 Cac-phan-Ung-Oxi-hoa-khu-thuong-gap-trong chuong trinh pho thong

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Gio khoa ha v c Bin son: V Hng Thi

http://vietsciences.free.fr v http://vietsciences.org V Hng Thi

169

Chng trnh Ha hc

VN III HA V C

VIT CC PHN NG OXI HA KHTHNG GP

(CC CHT OXI HA, CHT KHTHNG GP)

vit c cc phn ng oxi ha kh th chng ta cn bit mt s cht oxi ha v mts cht kh thng gp. Cht oxi ha sau khi b kh th to thnh cht kh lin hp (chtkh tng ng); Cng nh cht kh sau khi b oxi ha th to thnh cht kh lin hp(cht kh tng ng). Ta phi bit cc cht kh v cht oxi ha tng ng th mi vitc phn ng oxi ha kh.

I. Cc cht oxi ha thng gp

I.1. Cc hp cht ca mangan: KMnO4, K2MnO4, MnO2 (MnO4-, MnO4

2-, MnO2)

+7 +6 +4

- KMnO4, K2MnO4, MnO2 trong mi trng axit (H+) thng b khthnh mui

+2

Mn2+

Th d:+7 +2 +2 +32KMnO4 + 10FeSO4 + 8H2SO4 2MnSO4 + 5Fe2(SO4)3 + K2SO4 + 8H2OKali pemanganat St (II) sunfat Mangan (II) sunfat St (III) sunfatThuc tm(Cht oxi ha) (Cht kh)

+7 +3 +2 +5

2KMnO4 + 5KNO2 + 3H2SO4 2MnSO4 + 5KNO3 + K2SO4 + 3H2OKali nitrit Kali nitrat

(Cht oxi ha) (Cht kh)

+7 +4 +2 +6

2KMnO4 + 5K2SO3 + 3H2SO4 2MnSO4 + 6K2SO4 + 3H2OKali sunfit Kali sunfat


+6 +2 +2 +3

K2MnO4 + 4FeSO4 + 4H2SO4 MnSO4 + 2Fe2(SO4)3 + K2SO4 + 4H2OKali manganat St (II) sunfat Managan (II) sun fat St (III) sunfat(Cht oxi ha) (Cht kh)

+4 -1 +2 0

MnO 2 + 4HCl() 0t MnCl2 + Cl2 + 2H2O


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170

Mangan ioxit Axit clohric (c) Mangan(II) clorua Kh clo(Cht oxi ha) (Cht kh)

+4 +2 +2 +3MnO2 + 2FeSO4 + 2H2SO4 MnSO4 + Fe2(SO4)3 + 2H2O

Mangan ioxit St (II) sunfat Mangan (II) sunfat St (III) sunfat(Cht oxi ha) (Cht kh)

+7 -1 +2 0

2KMnO4 + 10NaCl + 8H2SO4 2MnSO4 + 5Cl2 + K2SO 4 + 5Na2SO4 + 8H2OKali pemanganat Nat ri clorua Mangan (II) sunfat Kh clo(Cht oxi ha) (Cht kh)

+7 -1 +2 0

2KMnO4 + 16HCl 2MnCl2 + 5Cl2 + 2KCl + 8H2O

Kali pemanganat Axit clohric Mangan (II) clorua Kh clo(Cht oxi ha) (Cht kh)

+7 +2 +2 +3

MnO 4- + 5Fe2+ + 8H+ Mn2+ + 5Fe3+ + 4H2O

Ion pemanganat Ion st (II) Ion mangan (II) Ion st (III)(Cht oxi ha) (Cht kh)

+7 -3 +2 +5

8KMnO4 + 5PH3 + 12H2SO4 8MnSO4 + 5H3PO4 + 4K2SO4 + 12H2OKali pemanganat Photphin Mangan (II) sunfat Axit sunfuric(Cht oxi ha) (Cht kh)

+7 0 +2 +2

2KMnO4 + 5Zn + 8H2SO4 2MnSO4 + 5ZnSO4 + K2SO4 + 8H2OKm

+7 +3 +3 +2 +4

2KMnO4 + 5HOOC-COOH + 3H2SO4 2MnSO4 + 10CO2 + K2SO4 + 8H2OAxit oxalic Kh cacbonic


- KMnO4 trong mi trng trung tnh (H2O) thng b khthnh mangan ioxit(MnO2)

Th du:

+7 +4 +4 +62KMnO4 + 4K2SO3 + H2O MnO2 + K2SO4 + KOHKali pemanganat Kali sunfit Man ganioxit Kali sunfat(Cht oxi ha) (Cht kh)

+7 +2 +4

2KMnO4 + 3MnSO4 + 2H2O 5MnO2 + K2SO4 + 2H2SO4Kali pemanganat Mangan (II) sunfat Mangan ioxit(Cht oxi ha) (Cht kh)


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171

+7 -1 +4 0

2KMnO4 + 3H2O2 2MnO2 + 3O2 + 2KOH + 2H2OHiro peoxit Mangan ioxit Kh oxi(Cht oxi ha) (Cht kh)

- KMnO4 trong mi trng baz(OH-) thng b khto K2MnO4

Th d:

+7 +4 +6 +4

2KMnO4 + K2SO3 + 2KOH 2K2MnO4 + K2SO4 + H2OKali pemanganat Kali sunfit Kali manganat Kali sunfat


+7 +3 +3 +6 +4

2KMnO4 + KOOC-COOK + 2KOH 2K2MnO4 + 2KHCO3Kali pemanganat Kali oxalat Kali manganat Kali cacbonat axit(Cht oxi ha) (Cht kh)

+7 -2 +6 0

2KMnO4 + 2KOH 2K2MnO4 +2

1O2 + H2O

Kali pemanganat Kali manganat Oxi(Cht oxi ha cng l cht kh) (Phn ng oxi ha kh ni phn t)

Ghi ch

G.1. KMnO4 trong mi trng axit (thng l H2SO4) c tnh oxi ha rt mnh, nn nd b mt mu tm bi nhiu cht kh nh: Fe2+; FeO; Fe3O4; SO2; SO3

2-; H2S; S2-;

NaCl; HCl; KBr, HBr, HI; KI; Cl-; Br-; I-; NO2-; Anken; Ankin; Ankaien; Aren

ng ng benzen;

Th d: +4 +7 +6 +25SO2 + 2KMnO4 + 2H2O 2H2SO4 + 2MnSO4 + K2SO4

Kh sunfur Kali pemanganat Axit sunfuric Mangan (II) sunfat(Cht kh) (Cht oxi ha)

Kh sunfurlm mt mu tm ca dung dch KMnO4 (dung dch thuc tm), trong SO2ng vai tr chtkh. Kh SO2 v CO2u lm c nc vi trong (v c to cht khng tan CaSO3, CaCO3), nhng CO2khng lm mt mu dung dch KMnO4.

G.2. lm mi trng axit (H+) cho cc cht oxi ha th ngi ta thng dng H2SO4hay H3PO4 m khng dng cc axit HCl, HBr, HI v cc axit ny ngoi s cung cpH+, chng cn ng vai tr cht kh (Cl-, Br-, I-).


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G.3. KMnO4 c thng vai tr cht oxi ha trong mi trng axit (H+), baz (OH-)

hoc trung tnh (H2O). Cn K2MnO4, MnO2 ch c thng vai tr cht oxi hatrong mi trng axit.

G.4.Ngi ta dng KMnO4 trong dung dch KOH m cra dng c thy tinh.

II.2. Hp cht ca crom: K2Cr2O7; K2CrO4 (Cr2O72-; CrO4

2-)

K2Cr2O7 (Kali icromat; Kali bicromat), K2CrO4 (Kali cromat) trong mi trng axit(H+) thng b khthnh mui crom (III) (Cr3+)Th d:

+6 +2 +3 +3

K2Cr2O7 + 6FeSO4 + 7H2SO4 Cr2(SO4)3 + 3Fe2(SO4)3 + K2SO4 + 7H2OKali icromat St (II) sunfat Crom (III) sunfat St (III) sunfat


+6 +4 +3 +6

K2Cr2O7 + 3K2SO3 + 4H2SO4 Cr2(SO4)3 + 4K2SO4 + 4H2OKali icromat Kali sunfit Crom (III) sunfat Kali sunfat(Cht oxi ha) (Cht kh)

+6 -1 +3 0

K2Cr2O7 + 6KI + 7H2SO4 Cr2(SO4)3 + 3I2 + 4K2SO4 + 7H2OKali icromat Kali ioua Crom (III) sunfat Iot


+6 -2 +3 0K2Cr2O7 + 3H2S + 4H2SO4 Cr2(SO4)3 + 3S + K2SO4 + 7H2O

Kali icromat Hi ro sun fua Crom (III) sunfat Lu hunh(Cht oxi ha) (Cht kh)

+6 -1 +3 0

K2Cr2O7 + 14HBr 2CrBr3 + 3Br2 + 2KBr + 7H2OKali icromat Axit bromhric Crom (III) bromua Brom Kali bromua(Cht oxi ha) (Cht kh)

+6 -1 +3 0

K2Cr2O7 + 14HCl 2CrCl3 + 3Cl2 + 2KCl + 7H2O

Kali icromat Axit clohiric Crom (III) clorua Clo Kali clorua(Cht oxi ha) (Cht kh)

+6 +2 +3 +4

K2Cr2O7 + 3SnCl2 + 14HCl 2CrCl3 + 3SnCl4 + 2KCl + 7H2OKali icromat Thic (II) clorua Axit clohiric Crom (III) clorua Thic (IV) clorua(Cht oxi ha) (Cht kh)

+6 -1 +3 +1

K2Cr2O7 + 3CH3CH2OH + 4H2SO4 Cr2(SO4)3 + 3CH3CHO + K2SO4 + 7H2OKali icromat Ru etylic Crom (III) sunfat Anehit axetic(Cht oxi ha) (Cht kh)


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173

+6 +4 +3 +6

K2Cr2O7 + 3SO2 + H2SO4 Cr2(SO4)3 + K2SO4 + H2OKali icromat Kh sunfur Crom (III) sunfat Kali sunfat


Ghi ch

G.1. Trong cc phn ng trn, mu da cam ca dung dch K2Cr2O7 trthnh mu tmca ion Cr3+ trong nc. Do trong ha phn tch, K2Cr2O7 trong mi trngaxit thng c dng lm cht oxi ha chun cc cht kh(Cn c smt mu va dung dch K2Cr2O7 s bit c lng K2Cr2O7 phn ng va v t bit c nng ca dung dch cht kh cn xc nh)

G.2. Ngi ta thng dng hn hp gm hai th tch bng nhau ca dung dch axit

sunfuric m c (H2SO4) v dung dch bo ha kali icromat (K2Cr2O7), gi lhn h p sunfocromic hay hn h p cromic, sc cc chai l thy tinh. Dungdch ny ty m, cng nh cc cht hu cbm vo thnh thy tinh, nh tnh oxiha mnh ca dung dch ny.

G.3. Trong mi trng trung tnh, mui cromat (CrO42-) thng b khto crom (III)

hiroxit (Cr(OH)3)

Th d:+6 -2 +3 0

2KCrO4 + 3(NH4)2S + 2H2O 2Cr(OH)3 + 3S + 6NH3 + 4KOHKali cromat Amoni sunfua Crom (III) hiroxit Lu hunh(Cht oxi ha) (Cht kh)

G.4. Ngi ta dng CrO3 (Crom (VI) oxit, Anhirit cromic, cht rn c mu thm)trong dng cth cn ca ti x. CrO3 oxi ha hi ru etylic (CH3CH2OH)to anehit axetic (CH3CHO), cn CrO3 b kh to crom (III) oxit (Cr2O3, cht rnc mu xanh thm). Cn c vo mc i mu hay khng i mu ca CrO3 mcnh st giao thng bit c ngi li xe ung ru nhiu, t hay khng ungru.

+6 -1 +3 +1

2CrO3 + 3CH3CH2OH Cr2O3 + 3CH3CHO + 3H2OAnhirit cromic Etanol Crom (III) oxit Eta nal( thm) (Xanh thm)


G.4. Gia icromat (Cr2O72-, mu da cam) v cromat (CrO4

2-, c mu vng ti)trong dung dch (nc, H2O) c scn bng do sthy phn nh sau:

Cr2O72- + H2O 2CrO4

2- + 2H+icromat Cromat(mu da cam) (mu vng)


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Do khi cho a xit (H+, nh HCl) vo mt dung dch cromat (CrO42-, nh K2CrO4)

th thy dung dch chuyn t mu vng sang mu da cam. Nguyn nhn l khithm axit vo th nng ion H+ tng ln, nn theo nguyn l dch chuyn cn bngLe Chtelier, th cn bng dch chuyn theo chiu lm h nng ion H+ xung, tctheo chiu ion H+ kt hp ion cromat to ion icromat v th ta thy dung dchchuyn t mu vng sang mu da cam. Cn khi thm baz (OH-, nh NaOH)vo dung dch icromat (Cr2O7

2-, nh K2Cr2O7) th thy dung dch chuyn t mu da cam ra mu vng. Nguyn nhn l khi thm OH- vo th ion OH- s kt hpion H+ (to cht khng in ly H2O) khin cho nng ion H

+ trong dung dchgim, nn theo nguyn l dch chuyn cn bng, cn bng s dch chuyn theo chiuchng li s gim ion H+, tc l chiu to ion H+, cng l chiu to cromat, v th tathy dung dch chuyn t mu da cam ra mu vng ti.

2K2CrO4 + 2HCl K2Cr2O7 + 2KCl + H2O(Mu da cam) (Mu vng ti)

K2Cr2O7 + 2NaOH K2CrO4 + Na2CrO4 + H2O(Mu da cam) Natri cromat

(Mu vng ti)

2Na2CrO4 + H2SO4 Na2Cr2O7 + Na2SO4 + H2O Natri cromat Natriicromat

Na2Cr2O7 + 2KOH Na2CrO4 + K2CrO4 + H2O

G.5. Khi cho dung dch mui bari (Ba2+, nh BaCl2, Ba(NO3)2) vo dung dch cromat(CrO4

2-) hay dung dch icromat (Cr2O72-) u thu c kt ta mu vng bari

cromat (BaCrO4). Khng thu c bari icromat (BaCr2O7) v cht ny tan trongnc. V v c to kt ta BaCrO4, nn nng CrO4

2- gim, nn cn bng dchchuyn t Cr2O7

2- thnh CrO42- (nu cho Ba2+ vo Cr2O7

2-, coi s cn bng giaicromat v cromat ghi ch 4 trn).

BaCl2 + K2CrO4 BaCrO4 + 2KClBari clorua Kali cromat Bari cromat Kali clorua

BaCl2 + K2Cr2O7 + H2O BaCrO4 + K2CrO4 + 2HClBari clorua Kali icromat Bari cromat Kali cromat Axit clohiric

Ba(NO3)2 + Na2Cr2O7 + H2O BaCrO4 + Na2CrO4 + 2HNO3Bari nitrat Natri icromat Bari cromat Natri cromat Axit nitric

I.3. Axit nitric (HNO3), mui nitrat trong mi trng axit (NO3-/H+)

+5 +4

- HNO3m c thng b kh to kh mu nu nitioxit NO2. Cc cht kh thngb HNO3 oxi ha l: cc kim loi, cc oxit kim loi c s oxi ha trung gian (FeO,Fe3O4), mt s phi kim (C, S, P), mt s hp cht ca phi kim c s oxi ha thp nht


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hay trung gian (H2S, SO2, SO32-, HI), mt s hp cht ca kim loi trong kim loi

c s oxi ha trung gian (Fe2+, Fe(OH)2

Th d:

0 +5 +3 +4

Fe + 6HNO3 (, nng) Fe(NO3)3 + 3NO2 + 3H2OSt Axit ntric St (III) nitrat Nitioxit

(Cht kh) (Cht oxi ha) (Kh c mi hc, mu nu)Trong 6 phn t HNO3 trn th ch c 3 phn t l cht oxi ha, cn 3 phn t to mi trng axit, to muinitrat.

+2 +5 +3 +4

FeO + 4HNO3() Fe(NO3)3 + NO2 + 2H2OSt (II) oxit

+8/3 +5 +3 +4

Fe3O4 + 10HNO3() 3Fe(NO3)3 + NO2 + 5H2OSt t oxit(Cht kh) (Cht oxi ha) (1 phn t HNO3 l cht o xi ha, 9 phn t tham gia trao i)

+2 +5 +3 +4

Fe(OH)2 + 4HNO3() Fe(NO3)3 + NO2 + 3H2OSt (II) hiroxit St (III) nitrat(Cht kh) (Cht oxi ha) (1 phn t HNO3 l cht oxi ha, 3 phn t trao i, to mi trng axit)

0 +5 +4 +4

C + 4HNO3() 0t CO2 + 4NO2 + 2H2OCacbon Kh cacbonic Nitioxit(Cht kh) (Cht oxi ha)(Cho tng git dd HNO3m c vo than nung nng, than bng chy)

0 +5 +6 +4

S + 6HNO3() 0t H2SO4 + 6NO2 + 2H2O

Lu hunh Axit nitric Axit sunfuric Nitioxit(Cht kh) (Cht oxi ha)(Cho bt lu hunh vo dd HNO3 m c c un nh, thy bt lu hunh tan nhanh v c kh munu bay ra)

0 +5 +5 +4

P + 5HNO3() 0t H3PO4 + 5NO2 + H2O

Photpho Axit photphoric(Cht kh) (Cht oxi ha)

0 +5 +1 +4

Ag + 2HNO3() AgNO3 + NO2 + H2OBc Bc nitrat

(Cht kh) (Cht oxi ha)


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0 +5 +2 +4

Cu + 4HNO3() Cu(NO3)2 + 2NO2 + 2H2Ong ng (II) nitrat


0 +5 +2 +4

Pb + 4HNO3() Pb(NO3)2 + 2NO2 + 2H2OCh Ch (II) nitrat


Al + 6HNO3(, nng) Al(NO3)3 + 3NO2 + 3H2O

+5 +2

- HNO3 long thng b kh thnh NO (kh nitoxit). Cc cht kh thng gp l: cckim loi, cc oxit kim loi hay h p cht kim loi c s oxi ha trung gian (FeO,

Fe(OH)2, Fe3O4, Fe2+

), mt s phi kim (S, C, P), mt s hp cht ca phi kim trong phi kim c s oxi ho thp nht c s oxi ha trung gian (NO2-, SO3

2-).

Th d:

0 +5 +3 +2

Fe + 4HNO3(l) Fe(NO3)3 + NO + 2H2OBt st Axit nitric (long) St (III) nitrat Nitoxit

(Cht kh) (Cht oxi ha) (Kh khng c, khng khng c mu)

+2 +5 +3 +2

3Fe(OH)2 + 10HNO3(l) 3Fe(NO3)3 + NO + 8H2OSt (II) hiroxit St (III) nitrat(Cht kh) (Cht oxi ha)

+2 +5 +3 +2

3FeO + 10HNO3(l) 3Fe(NO3)3 + NO + 5H2OSt (II) oxit St (III) nitrat(Cht kh) (Cht oxi ha)

+8/3 +5 +3 +2

3Fe3O4 + 28HNO3(l) 9Fe(NO3)3 + NO + 14H2OSt t oxit(Cht kh) (Cht oxi ha)

0 +5 +3 +2

Cr + 4HNO3(l) Cr(NO3)3 + NO + 2H2OCrom Crom (III) nitrat(Cht kh) (Cht oxi ha)

0 +5 +2 +2

3Cu + 8HNO3(l) 3Cu(NO3)2 + 2NO + 4H2Ong ng (II) nitrat(Cht kh) (Cht oxi ha)


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0 +5 +1 +2

3Ag + 4HNO3(l) 3AgNO3 + NO + 2H2OBc Bc nitrat


0 +5 +2 +2

3Hg + 8HNO3(l) 3Hg(NO3)2 + 2NO + 4H2OThy ngn Thy ngn (II) nitrat(Cht kh) (Cht oxi ha)

0 +5 +6 +2S + 2HNO3(l) H2SO4 + 2NO

Lu hunh Axit nitric (long) Axit sunfuric Nitoxit

0 +5 +5 +2

3P + 5HNO3(l) + 2H2O 3H3PO4 + 5NOPhotpho Axit nitric (long) Axit photphoric


- Mui nitrat trong mi trng axit (NO3-/H+) ging nhHNO3 long, nn n oxi ha

c cc kim loi to mui, NO3- b kh to kh NO, ng thi c s to nc (H2O)

Th d:

0 +5 +2 +2

3Cu + 2NO3- + 8H+ 3Cu2+ + 2NO + 4H2O

ng Mui nitrat trong mi trng axit Mui ng (II)

(Cht kh) (Cht oxi ha) (Dung dch c mu xanh lam)

Kh NO khng mu thot ra kt hp vi O2 (ca khng kh) to kh NO2 c mu nu

0 +5 +2 +2

3Cu + 2NaNO3 + 8HCl 3CuCl2 + 2NO + 2NaCl + 4H2O

0 +5 +2 +2

3Cu + Cu(NO3)2 + 8HCl 4CuCl2 + 2NO + 4H2OCht kh Cht oxi ha

Ghi ch

G.1. Ba kim loi st (Fe), nhm (Al) v crom (Cr) khng b ha tan trong dung dchaxit nitric m c ngui (HNO3 , ngui) cng nh trong dung dch axitsunfuric m c ngui (H2SO4, ngui) (b thng ha, b tr).

Fe, Al, Cr HNO3(, ngui)

Fe, Al, Cr H2SO4(, ngui)


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G.2. nhn bit mui nitrat, ngi ta cho vi git dung dch axit thng thng(nh H2SO4 long, HCl) vo, sau cho ming kim loi ng vo, nu thy todung dch mu xanh lam v c kh mu nu bay ra th chng t dung dch lcu c cha mui nitrat ((NO3-).

G.3. Cc kim loi mnh nh magie (Mg), nhm (Al), km (Zn) khng nhng kh+5 +4 +2 +1 0 -3

HNO3 to NO2, NO, m c th to N2O, N2, NH4NO3. Dung dch HNO3 cnglong th b kh to hp cht ca N hay n cht ca N c s oxi ha cng thp.

Th d:

Al + HNO3(, ngui)

Al + 6HNO3(, nng) Al(NO3)3 + 3NO2 + 3H2O

Al + 4HNO3(l) Al(NO3)3 + NO + 2H2O

8Al + 30HNO3(kh long) 8Al(NO3)3 + 3N2O + 15H2O

10Al + 36HNO3(rt long) 10Al(NO3)3 + 3N2 + 18H2O

8Al + 30HNO3(qu long) 8Al(NO3)3 + 3NH4NO3 + 9H2O

G.4. Dung dch HNO3 rt long v lnh c tc dng nh mt axit thng thng (tcnhn oxi ha l ion H+)

Th d:

Al + 3HNO3(rt long) lnh Al(NO3)3 +2

3H2

Fe + 2HNO3(rt long) lnh Fe(NO3)2 + H2

G.5. Mt kim loi tc dng dung dch HNO3 to cc kh khc nhau, tng qut mi khng vi mt phn ng ring. Ch khi no bit t l s mol cc khny th mi

vit chung cc kh trong cng mt phn ng vi t l s mol kh tng ng.

Bi tp 80Cho m gam bt kim loi km ha tan ht trong dung dch HNO3, thu c 13,44 lt hnhp ba kh l NO2, NO v N2O. Dn lng kh trn qua dung dch xt d, c 11,2 lt hnhp kh thot ra. Cho lng kh ny trn vi khng kh d (coi khng kh ch gm oxi vnit) phn ng xy ra hon ton, sau cho hp th lng kh mu nu thu c vodung dch KOH d, thu c dung dch D. Dung dch D lm mt mu va 100 mldung dch KMnO4 0,4M trong mi trng H2SO4 c d. Th tch cc kh o ktc. Ccphn ng xy ra hon ton.


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a. Vit phn ng gia km vi dung dch HNO3 c hin din 3 kh trong phn ngtheo d kin trn.

b. Tnh m.(Zn = 65)

S: 31Zn + 80HNO3 31Zn(NO3)2 + 2NO2 + 4NO + 6N2O + 40H2Om = 100,75 gam

Bi tp 80Ha tan ht m gam bt nhm cn dng V(ml) dung dch HNO3 30% (khi lng ring1,18 g/l), c 1,568 lt hn h p A gm ba kh NO, N2O v N2 thot ra ( 27,3

0C; 836mmHg), ng thi thu c dung dch D (trong dung dch D khng c mui amoni). Cholng kh trn tip xc khng kh kh NO chuyn ha ht thnh kh mu nu NO2 , sau cho lng kh nu ny hp th ht vo bnh ng dung dch xt d, thy khi lngbnh tng 0,92 gam.

a. Xc nh % th tch mi kh trong hn hp A, bit rng khi lng ring ktcca hn hp A l 1,4796 g/l.

b. Vit phn ng gia nhm vi dung dch HNO3 theo d kin cho.c. Xc nh m v V.

(N = 14; O = 16; H = 1; Al = 27)S: a. 28,57% NO; 28,57% N2O; 42,86% N2

b. 52Al + 192HNO3 52Al(NO3)3 + 6NO + 6N2O + 9N2 + 96H2Oc. m = 4,68g; V = 113,898 ml

I.4. Axit sunfric m c nng, H2SO4(, nng); Kh sunfur(SO2)+6 +4

- H2SO4(, nng) thng b kh to kh SO2. Cc cht kh thng tc dng viH2SO4(, nng) l: cc kim loi, cc hp cht ca kim loi s oxi ha trung gian (nhFeO, Fe3O4), mt s phi kim (nh C, S, P), mt s hp cht ca phi kim (nh HI,HBr, H2S)

Th d:0 +6 +2 +4

Cu + 2H2SO4(, nng) CuSO4 + SO2 + 2H2Ong Axit sunfuric (c, nng) ng (II) sunfat Kh sunfur(Cht kh) (Cht oxi ha)

0 +6 +3 +4

2Fe + 6H2SO4(, nng) Fe2(SO4)3 + 3SO2 + 6H2OSt St (III) sunfat

0 +6 +1 +4

2Ag + 2H2SO4(, nng) Ag2SO4 + SO2 + 2H2OBc Bc sunfat

+2 +6 +3 +4

2FeO + 4H2SO4(, nng) Fe2(SO4)3 + SO2 + 4H2OSt (II) oxit St (III) sunfat(Cht kh) (Cht oxi ha)


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+8/3 +6 +3 +4

2Fe3O4 + 10H2SO4(, nng) 3Fe2(SO4)3 + SO2 + 10H2OSt t oxit St (III) sunfat Kh sunfur

Fe2O3 + 3H2SO4(, nng) Fe2(SO4)3 + 3H2O (phn ng trao i)St (III) oxit St (III) sunfat

0 +6 +3 +4

Cr + H2SO4(, nng) Cr2(SO4)3 + SO2 + H2OCrom Crom (III) sunfat

0 +6 +4

S + 2H2SO4(, nng) 3SO2 + 2H2OLu hunh Axit sunfuric m c nng Kh sunfur


0 +6 +4 +4

C + 2H2SO4(, nng) CO2 + 2SO2 + 2H2OCacbon


0 +6 +5 +4

2P + 5H2SO4(, nng) 2H3PO4 + 5SO2 + 2H2OPhotpho Axit photphoric


-1 +6 0 +42HI + H2SO4(, nng) I2 + SO2 + 2H2O

Axit iothiric Iot Kh sunfur(Cht kh) (Cht oxi ha)

-1 +6 0 +4

2HBr + H2SO4(, nng) Br2 + SO2 + 2H2OAxit bromhiric Brom Kh sunfur


-2 +6 0 +4

H2S + H2SO4(, nng) S + SO2 + 2H2O

Axit sun fuahiric Lu hunh Kh sunfur(Cht kh) (Cht oxi ha)

- Cc kim loi mnh nhMg, Al, Zn khng nhng khH2SO4m c, nng thnhSO2 m cn thnh S, H2S. H2SO4m c nhng nu long bt th s b kh to luhunh (S) hay hp cht ca lu hunh c s oxi ha thp hn (H2S). Nguyn nhnca tnh cht trn l do kim loi mnh nn d cho in t ( H2SO4 nhn nhiu int) v do H2SO4 t m c nn n khng oxi ha tip S, H2S.

Th d:


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181

Al + H2SO4(, ngui)

0 +6 +3 +4

2Al + 6H2SO4(, nng) Al2(SO4)3 + 3SO2 + 6H2O Nhm Kh sunfur

0 +6 +3 0

2Al + 4H2SO4(kh c, nng) Al2(SO4)3 + S + 4H2OLu hunh

0 +6 +3 -2

8Al + 15H2SO4(hi c, nng) 4Al2(SO4)3 + 3H2S + 12H2OHiro sunfua

0 +1 +3 0

2Al + 3H2SO4(long) Al2(SO4)3 + 3H2Hiro

- Kh sunfur(SO2) oxi ha c cc cht kh mnh nh cc hp cht ca phi kim cs oxi ho thp (nh H2S, CO), mt s phi kim (nh H2, C), cc kim loi mnh (nhNa, K, Ca, Ba, Mg). Nu SO2 l cht oxi ha th n thng b khto S.

+4 -2 0

SO2 + H2S S + H2OKh sunfur Kh hiro sunfua Lu hunh(Cht oxi ha) (Cht kh)

Kh mi hc Kh c mi trng thi Cht rn, mu vng nht+4 +2 0 +4

SO2 + 2CO COAlXt 032 500)( S + CO2


+4 0 0 +2

SO2 + 2C C0800 S + 2CO


+4 0 0 +1

SO2 + 2H2 C0500 S + 2H2O


+4 0 0 +2

SO2 + 2Mg 0t S + 2MgO


Ghi chG.1. Khc vi HNO3, dung dch H2SO4 long l a xit thng thng (tc nhn oxi ha

l H+), ch dung dch H2SO4m c, nng mi l axit c tnh oxi ha mnh (tcnhn oxi ha l SO4

2-). Trong khi dung dch HNO3 k cm c ln long u laxit c tnh o xi ha mnh (tc nhn oxi ha l NO3

-)


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183

b. Tnh nng mol/lt ca dung dch H2SO4.c. Cho t t V (lt) dung dch NaOH 0,1M vo lng dung dch Y trn. Tm khong

xc nh ca V hoc tr s ca V :. Khng c kt ta.. Thu c kt ta nhiu nht. Tnh khi lng kt ta nhiu nht ny.

Cc phn ng xy ra hon ton.(Li = 7; Be = 9; Na = 23; Mg = 24; Al = 27; Ca = 40; Cr = 52; Mn = 55; Fe = 56; Ni =

59; Cu = 64; Ag = 108; Hg = 200; Pb = 208; O = 16; H = 1; S = 32)S: Al; H2SO4 7M; 2,04lt V 7,64lt; V = 6,24lt ; 10,92gam Al(OH)3

I.5. Ion H+

- Ion H+ ca axit thng thng oxi ha c cc kim loi ng trc H trong dythin ha. Ion H+ b kh to kh H2, cn kim loi b kh to mui tng ng (ionkim loi).

K Ca Na Mg Al Mn Zn Cr Fe Ni Sn Pb H Cu Ag Hg Pt Au

Th d:Zn + 2HCl ZnCl2 + H2

0 +1 +2 0

Zn + 2H+ Zn2+ + H2(Cht kh) (Cht oxi ha) (Cht oxi ha) (Cht kh)

Phn ng trn xy ra c l do: Tnh kh: Zn > H2Tnh oxi ha: H+ > Zn2+

Fe + H2SO4(l) FeSO4 + H2

0 +1 +2 0

Fe + 2H+ Fe2+ + H2(Cht kh) (Cht oxi ha) (Cht oxi ha) (Cht kh)

Phn ng trn xy ra c l do: Tnh kh: Fe > H2Tnh oxi ha: H+ > Fe2+

Al + 3HBr AlBr3 +23 H2

0 +1 +3 0

Al + 3H+ Al3+ +2

3H2

(Cht kh) (Cht oxi ha) (Cht oxi ha) (Cht kh)

Phn ng trn xy ra c l do: Tnh kh: Al > H2Tnh oxi ha: H+ > Al3+


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184

Na + HCl NaCl +2

1H2

Cu + HCl

Ag + H2SO4(l)

Cr + 2HCl CrCl2 + H2Crom Crom (II) clorua

Mg + 2CH3COOH Mg(CH3COO)2 + H2Magie Axit axetic Magie axetat

Ni + 2HCl NiCl2 + H2 Niken Niken clorua

Hg + HBrThy ngn

- Ion H+ ca nc (H2O) nhit thng ch oxi ha c cc kim loi rt mnh lkim loi kim (Li, Na, K, Rb, Cs, Fr) v kim loi kim th (Ca, Sr, Ba, Ra). Kimloi kim, kim th b oxi ha to hiroxit kim loi, cn H+ ca nc b kh thnh khhiro (H2). V nng ion H

+ ca nc rt nh, nn nhit thng n ch oxi hacc kim loi rt mnh l kim, kim th, m khng oxi ha c cc kim loi khc.

Th d:0 +1 +1 0

2Na + 2H2O 2NaOH + H2 Natri Nc Natri hiroxit Kh hiro(Cht kh ) (Cht oxi ha)

2K + 2H2O 2KOH + H2Kali

0 +1 +2 0

Ca + 2H2O Ca(OH)2 + H2Canxi Nc Canxi hiroxit Hiro

(Cht kh ) (Cht oxi ha)

Ba + 2H2O Ba(OH)2 + H2Bari Nc Bari hiroxit Hiro

Al + H2O

Mg, Fe, Cu, Ag


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185

- Ion H+ ca nc (H2O) c th oxi ha cc kim loi ng trc H trong dy thinha nhit cao, kim loi b oxi ha to oxit kim loi, cn H+ ca nc b kh tothnh kh H2. V nhit cao nn hiroxit kim loi bi nhit phn nn ta khng thuc hiroxit kim loi m l oxit kim loi.

Th d:

Fe + H2O

3Fe + 4H2O < 5700C Fe3O4 + 4H2St Hi nc St t oxit Hiro

Fe + H2O > 5700C FeO + H2St Hi nc St (II) oxit Hiro

Mg + H2O

0 +1 +2 0

Mg + H2O caot0 MgO + H2

Magie Hi nc Magie oxit Hiro

Cu + H2O

Cu + H2O t0

Zn + H2O

Zn + H2O caot0 ZnO + H2

Km Km oxit

Ghi ch

G.1. Khi cho kim loi kim (Li, Na, K, Rb, Fr) kim th (Ca, Sr, Ba, Rn) tc dngvi dung dch axit thng thng th kim loi kim, kim th tc dng vi H+ca axit trc (to mui v kh H2), khi ht axit m cn d kim loi kim, kimth, th kim loi kim, kim th mi tc dng tip vi dung mi nc ca dung

dch sau (to hiroxit kim loi v kh H2).

Th d:

Cho Na vo dung dch HCl:2Na + 2HCl 2NaCl + H2

Ht HCl m cn d:2Na(cn d) + 2H2O 2NaOH + H2


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186

Cho Ba vo dung dch CH3COOH:Ba + 2CH3COOH Ba(CH3COO)2 + H2

Ht CH3COOH, cn Ba d:Ba + 2H2O Ba(OH)2 + H2

Bi tp 82Cho m gam kali kim loi vo 100 ml dung dch HCl 0,1M. Sau cn thm tip 10 mldung dch HBr 0,2M thu c dung dch c pH = 7.

a. Tnh m. b. Tnh th tch kh hiro thot ra trong th nghim trn 27,30C; 83,6 cmHg.c. Xc nh nng mol/lt ca dung dch c pH = 7 trn.

Cc phn ng xy ra hon ton. Coi th tch dung dch khng thay i trong qu trnh

phn ng. (K = 39)S: m = 0,468g; 134,4ml; KCl 0,091M; KBr 0,018M

Bi tp 82Cho m gam canxi kim loi vo 200 gam dung dch HBr 0,81%. Sau cn thm tip 50gam dung dch HCl 0,73% vo thu c dung dch D c pH = 7.

a. Tnh m. b. Tnh th tch kh thot ra ktc. Coi hi nc bay hi khng ng k.c. Xc nh nng % mi cht tan ca dung dch D.

Cc phn ng xy ra hon ton.(Ca = 40; H = 1; Br = 80; Cl = 35,5)

S: m = 0,6g; 336ml H2; CaBr2 0,8%; CaCl2 0,222%

I.6. Ion kim loi

Ion kim loi lun lun l ion dng. Tt c ion kim loi u c th l cht oxi ha. Nul cht oxi ha th n b kh to ion kim loi c s oxi ha thp hn hay thnh kimloi n cht tng ng.

- Ion kim loi (trong dung dch) oxi ha c cc kim loi ng trc n trong dy thin ha (tr kim loi kim, kim th).

K Ca Na Mg Al Mn Zn Cr Fe Ni Sn Pb H Cu Ag Hg Pt Au Chiu cc cht khc mnh gim dn

K+ Ca2+ Na+ Mg2+ Al3+ Mn2+ Zn2+ Cr3+ Fe2+ Ni2+ Sn2+ Pb2+ H+ Cu2+ Ag+ Hg2+ Pt2+ Au3+ Chiu cc cht oxi ha c mnh tng dn

Th d:

2FeCl3(dd) + Fe 3FeCl2(dd)


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187

+3 0 +22Fe3+ + Fe 3Fe2+

Cht oxi ha Cht kh

FeCl2(dd) + Zn Fe + ZnCl2(dd)

+2 0 0 +2

Fe2+ + Zn Fe + Zn2+

Cht oxi ha Cht kh

2Al + 3CuSO4(dd) Al2(SO4)3(dd) + 3Cu

0 +2 +3 0

2Al + 3Cu2+ 2Al3+ + 3Cu

Cht kh Cht oxi ha

Ag + Fe(NO3)3(dd)

3Zn(d) + 2Fe(NO3)3(dd) 3Zn(NO3)2(dd) + 2Fe

0 +3 +2 0

3Zn(d) + 2Fe3+ 3Zn2+ + 2FeCht kh Cht oxi ha

Zn + 2Fe(NO3)3(dd, d) Zn(NO3)2(dd) + 2Fe(NO3)2(dd)

Zn + 2Fe3+(d) Zn2+ + 2Fe2+AgNO3(dd) + Fe(NO3)3(dd)

AgNO3(dd) + Fe(NO3)2(dd) Ag + Fe(NO3)3(dd)

+1 +2 0 +3

Ag+ + Fe2+ Ag + Fe3+

Cht oxi ha Cht kh

Fe + Cu(CH3COO)2(d d) Fe(CH3COO)2 + Cu

Cu + FeSO4(dd) CuSO4(dd) + Fe

Cu + Fe2(SO4)3(dd) CuSO4 + 2FeSO4

+3 -2 -1 -1 +2 +2 +4 0 0

- Ion Fe3+(dd) oxi ha c H2S, HI, KI, Sn2+, Na2S2O3, SO3

2-, Cu, Fe. Fe3+ b khtoFe2+, cn cc cht kh trn b o xi ha to S, I2, I2, Sn

4+, Na2S4O6, SO42-, Cu2+,

Fe2+.


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188

Th d:+3 -2 +2 0

2FeCl3 + H2S 2FeCl2 + S + 2HClCht oxi ha Cht kh

+3 -1 +2 0

2FeCl3 + 2HI 2FeCl2 + I2 + 2HClCht oxi ha Cht kh

+3 -1 +2 0

2FeCl3 + 2KI 2FeCl2 + I2 + 2KClCht oxi ha Cht kh

+ 3 +2 +2 +4

2FeCl3 + SnCl2 2FeCl2 + SnCl4St (III) clorua Thic (II) clorua St (II) clorua Thic (IV) clorua(Cht oxi ha) (Cht kh)

+3 +2 +2 +2,5

2FeCl3 + 2Na2S2O3 2FeCl2 + Na2S4O6 + 2NaCl Natri tiosunfat; Natri hiposun fit Natri terationat


+3 +4 +2 +6

2FeCl3 + Na2SO3 + H2O 2FeCl2 + Na2SO4 + 2HCl Natri sunfit Natri sunfat


2FeCl3 + Cu 2FeCl2 + CuCl22FeCl3 + Fe 3FeCl2

Fe2(SO4)3 + 6KI 2FeI + I2 + 3K2SO4

Fe2(SO4)3(dd) + 3Na2S(dd, d) 2FeS + S + 3Na2SO4

Fe2(SO4)3(dd, d) + Na2S(dd, d) 2FeSO4 + S + Na2SO4

(Nu trong dung dch long, cn c s thy phn:Fe2(SO3)3 + 3Na2S 2Fe(OH)3 + H2S + 3Na2SO4)

Fe2(SO4)3(d) + 2KI 2FeSO4 + I2 + K2SO4

Fe2(SO4)3 + 6KI(d) 2FeI2 + I2 + 3K2SO4

Ch


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189

Do tnh oxi ha ca Fe3+, n oxi ha c I-, SO32-, S2-, nn khng c FeI3, Fe2(SO3)3,

Fe2S3 trong dung dch. Cng do s thy phn nhiu ca Fe3+ m khng c Fe2(CO3)3,

Fe2S3trong dung dch (S thy phn ca cc mui ny cp phn qui lut thcnghim s ha tan mui trong nc). S khng hin din Fe2S3 trong dung dch, c tiliu l do s thy phn, to Fe(OH)3 v H2S; C ti liu cho l do Fe

3+ oxi ha S2- toS, cn Fe3+ b kh to Fe2+. C l, khi dung dch long (c nhiu nc) th c s thyphn hoc c c s thy phn ln s oxi ha kh. Ni chung, khng thu c Fe2S3 trongdung dch.

Bi tp 83Hon hp chat ran A gom bot sat va muoi bac nitrat. Cho 250 ml H 2O vao coc co cham gam hon hp A. Khuay eu e phan ng xay ra hoan toan, thu c 5,4 gam motkim loai va 250 ml dung dch B co cha hon hp muoi. Cho t t bot kim loai ong vao

lng dung dch B tren th dung dch nay hoa tan c toi a 0,32 gam bot ong va thuc dung dch trong suot.a. Viet cac phng trnh phan ng xay ra.b. Tnh m.c. Tnh nong o mol/lt moi chat tan trong dung dch B.

(Fe = 56 ; Ag = 108 ; N = 14 ; O = 16 ; Cu = 64)S: m = 9,62g; Fe(NO3)2 0,04M; Fe(NO3)3 0,04M

Bi tp 83Hn hp cht rn X gm bt km v mui st (III) sunfat. Cho 200 ml nc vo mt bnhcha m gam hn hp X. Dng a thy tinh khuy u phn ng xy ra hon ton.

Thu c cht khng tan gm 3,36 gam mt kim loi v dung dch Y c ha tan hn hpmui. Cho dung dch xt lng d vo dung dch Y, sau khi phn ng xong, lc ly ktta em nung ngoi khng kh cho n khi lng khng i th thu c 11,2 gam mtcht rn.

a. Vit cc phn ng xy ra. b. Tnh m.c. Tnh nng mol ca cht tan ca dung dch Y. Coi th tch dung dch Y bng

th tch nc dng.(Zn = 65; Fe = 56; S = 32; O = 16)

S: m = 50,4g; ZnSO4 0,8M; FeSO4 0,7M

I.7. Halogen X2 v cc hp cht ca n, nh F2, Cl2, Br2, I2, NaClO, KClO3,Ca(ClO)2, CaCl2O, KBrO3, KIO3, HClO4. Cc cht oxi ha halogen n cht c soxi ha 0 hay hp cht ca halogen c s oxi ha +1, +3, +5, +7 thng b khtothnhmui halogenua X-(Cl-, Br-, I-) trong halogen c s oxi ha bng 1.

- Halogen nm chu k trn y c halogen nm chu k di ra khi dungdch mui halogenua. Hay halogen y c phi kim yu hn n ra khi dungdch mui cng nh axit. Thc cht cng l cht oxi ha mnh tc dng vi chtkh mnh trong dung dch to cht kh v cht oxi ha tng ng yu hn.


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Th d:Cl2 + 2KBr(dd) 2KCl(dd) + Br2

0 -1 -1 0

Cl2 + 2Br- (dd) 2Cl- (dd) + Br2

Cht oxi ha Cht kh Cht kh Cht oxi ha

Phn ng xy ra c l do: Tnh oxi ha: Cl2 > Br2Tnh kh: Br- > Cl-

0 -1 -1 0Br2 + 2KI 2KBr + I2

Brom Kali ioua Kali bromua Iot(Cht oxi ha) (Cht kh ) (Cht kh) (Cht oxi ha)

Phn ng xy ra c l do: Tnh oxi ha: Br2 > I2Tnh kh: I- > Br-

I2 + NaCl Br2 + KF

F2 + 2NaCl 2NaF + Cl2Flo (Fluor) Natri clorua Natri florua Clo

Cl2 + 2NaI 2NaCl + I2

Br2 + 2HI 2HBr + I2

I2 + H2S 2HI + S

0 +2 +3 0

3F2 + 2FeCl2(khan) 2FeF3 + 2Cl2

- Halogen X2 oxi ha c hu ht cc kim loi to mui halogenua X-. Ring

F2 (flo) c tnh oxi ha mnh nht, n phn ng c vi tt c cc kim loi (k

c vng v bch kim) to mui florua. F2, Cl2, Br2 tc dng Fe to mui st(III), ring I2 ch to mui st (II) (V Fe3+ oxi ha c I- to I2)

Th d:

2Na + Cl2 2NaCl

Natri nng chy chy trong bnh kh clo cho ngn la sng chi, to natri clorua.

2Fe + 3Cl2 2FeCl3 St (III) clorua


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191

Bt st nng chy trong bnh kh clo to thnh khi mu nu, l nhng ht rt nh st (III)clorua.

Fe +2

3F2 FeF3 St (III) florua

Fe +2

3Br2 FeBr3 St (III) bromua

Fe + I2 FeI2 St (II) ioua

Cu + Cl2 CuCl2

Nung si dy ng nng ri cho vo bnh kh clo, si dy ng chy sng, to ng (II) clorua.

2Al + 3Br2 2AlBr3

2Al + 3I2 2AlI3

- Cl2, Br2oxi ha c dung dch mui st (II) to mui st (III). Cl2 oxi ha H2Sto H2SO4. Br2, I2 o xi ho H2S to S.

+2 0 +3 -1

2FeCl2 + Cl2 2FeCl3St (II) clorua Clo St (III) clo rua(Cht kh) (Cht oxi ha)

+2 0 +3 +3 -1

2

3FeCl2 +

4

3Br2 FeCl3 +

2

1FeBr3

6FeCl2 + 3Br2 4FeCl3 + 2FeBr3

+2 0 +3 -1

2FeBr2 + Br2 2FeBr3

0 -2 -1 +6

4Cl2 + H2S + 4H2O 8HCl + H2SO4Clo Hiro sunfua Axit clohiric Axit sunfuric


Br2 + H2S 2HBr + SNu cho dung dch H2S (axit sunfuahiric) vo nc brom, th thy brom mt mu nu vdung dch c (do c to kt ta S)

I2 + H2S 2HI + S


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192

- X2 oxi ha c SO2 trong dung dch to H2SO4

0 +4 -1 +6

Cl2 + SO2 + 2H2O 2HCl + H2SO4Clo Kh sunfur Axit clohiric Axit sunfuric


0 +4 -1 +6

Br2 + SO2 + 2H2O 2HBr + H2SO4Brom Kh sunfur Axit bromhiric Axit sunfuric

(Cht oxi ha) (Cht kh)Kh SO2 lm mt mu nu ca nc brom

0 +4 -1 +6

I2 + SO2 + 2H2O 2HI + H2SO4Iot Kh sunfur Axit iothiric Axit sunfuric

(Cht oxi ha) (Cht kh)Kh SO2 lm mt mu vng ca dung dch iot.

- Cho lung kh flo (fluor, F2)i qua nc nng th nc bc chy v to ra khoxi

0 -2 -1 0

2F2 + 2H2O 0t 4HF + O2

Kh flo Hi nc Hiro florua Kh oxi(Cht oxi ha) (Cht kh)

Nc dp tt la m chy, nhng nc bc chy trong kh flo, gii phng khoxi. Do khi cho F2 tc dng vi dung dch NaCl khng thu c kh clo(Cl2) m l c phn ng gia kh F2 vi dung mi nc (H2O) ca dungdch to kh O2.

- X2oxi hac cc phi kim nh: H2, S, P

F2 + H2 2HF (Phn ng n mnh ngay c trong bng ti nhit rtthp, -2000C)

Cl2 + H2 as 2HCl ( nhit thng v trong bng ti, phn ng xy rart chm. Nhng khi un nng hay chiu sng mnh th

phn ng xy ra ngay v km theo ting n mnh)

Br2 + H2 0t 2HBr (Phn ng ch xy ra khi un nng)

I2 + H2 t0 cao 2HI (Phn ng ch xy ra khi un nng nhit cao vphn ng thun nghch)

2S + Cl2 S2Cl2


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193

P +2

3Cl2 PCl3

P +2

5Cl2 PCl5

P +2

3Br2 PBr3

2P + 3I2 0t 2PI3

- KClO3, NaClO, KBrO3, KIO3 oxi ha c cc cht kh nh: C, S, P, Fe2+,

S2- , SO32-, NH3. Cn cc cht oxi ha trn b kh to Cl-, Br-, I-

Th d:+5 0 1 +4

2KClO3 + 3C 0t 6KCl + 3CO2

Kali clo rat Cacbon Kali clo rua Kh cacbonic(Cht oxi ha) (Cht kh)

KClO3 + 6HCl KCl + 3Cl2 + 3H2O

+5 -1 -1 0

KClO3 + 6HBr KCl + 3Br2 + 3H2OKali clorat Axit bromhiric Kali clorua Brom(Cht oxi ha) (Cht kh)

+5 -1 -1 0

KBrO3 + 6HI KBr + 3I2 + 3H2OKali bromat Axit iothiric Kali bromua Iot


+1 -3 -1 0

3NaClO + 2NH3 3NaCl + N2 + 3H2O Natri hipoclorit Amoniac

(Cht oxi ha) (Cht kh)+1 -1 -1 0

NaClO + H2O2 NaCl + O2 + H2O Natri hipoclorit Hiropeoxit


+1 -1 -1 0

NaClO + 2KI + H2O NaCl + I2 + 2KOH


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194

+5 -1 -1 0

NaClO3 + 6KI + 3H2SO4 NaCl + 3I2 + 3K2SO4 + 3H2O Natri clorat Kali ioua Natri clorua Iot(Cht oxi ha) (Cht kh)

Lu

L.1. Khi cho kh clo vo dung dch xt, c phn ng:

0 -1 +1

Cl2 + 2NaOH NaCl + NaClO + H2OClo Natri clorua Natri hipoclorit

(Cht oxi ha, Cht kh) (Phn ng oxi ha kh ni phn t)

Sdc phn ng trn l do:

Cl2 + H2O HCl + HClOAxit clohiric Axit hipoclorit

HCl + NaOH NaCl + H2OHClO + NaOH NaClO + H2O

L.2. Dung dch hn hp cc mui NaCl - NaClO (hay KCl - KClO) c gi l ncJavel. Nc Javel c tnh oxi ha mnh (do c ion hipoclorit, ClO-), c dng ty trng si bng, vi v giy. Nc Javel khng c lu. Trong nh my dt,nh my giy, nc Javel c iu ch bng cch in phn dung dch NaCl long(15 20%) trong bnh in phn khng c vch ngn vi catod bng st v anodbng than ch (cacbon graphit).

L.3. Khi cho kh clo tc dng dung dch kim c un nng 1000C th thu cmui clorat.

0 -1 +5

3Cl2 + 6NaOH C0100 5NaCl + NaClO3 + 3H2O

Clo Natri clorua Natri clorat(Cht oxi ha, Cht kh) (Phn ng t oxi ha kh)

0 -1 +53Cl2 + 6KOH

C0100 5KCl + KClO3 + 3H2O

Clo Kali clorua Kali clorat(Cht oxi ha, Cht kh) (Phn ng t oxi ha kh)

Kali clorat d b nhit phn to kali clorua v kh oxi (khi un nng c MnO2 lmxc tc). Do KClO3c dng iu ch kh O2 trong phng th nghim. Vicc cht d b chy ( b kh) nh lu hunh (S), cacbon (than, C), photpho (P),bt nhm (Al), ng (C12H22O11) s to hn hp n vi KClO3 khi va chm (qut,p). V th, KClO3c dng lm thuc pho, thuc u que dim. Trong uca cy dim qut c cha 50% khi lng KClO3.


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KClO3 0

2 ,tMnO KCl +

2

3O2

Trong cng nghip, KClO3c iu ch bng cch cho kh cloi qua nc viun nng ri ly dung dch nng trn vi KCl v ngui cho KClO3 kttinh (v KClO3 t tan hn CaCl2). Kali clorat cn c iu ch bng cch inphn dung dch KCl 25% nhit 70 750C.

6Cl2 + 6Ca(OH)2 0t Ca(ClO3)2 + 5CaCl2 + 6H2O

Ca(ClO3)2 + 2KCl 2KClO3 + CaCl2Canxi hipoclorit Kali clorat

2KCl + 2H2O p, khng vch ngn, 750C, anod tr H2 + 2KOH + Cl2Catot Anot

6KOH + 3Cl2 0t 5KCl + KClO3 + 3H2O

(t tan hn KCl)

L.4. Clorua vi (CaOCl2) l cht bt mu trng, xp, c mi xc, lun bc mi kh clo.Clorua vi c coi l mui canxi hn tp ca axit clohiric (HCl) v axithipoclor (HClO). Clorua vi c tnh oxi ha mnh, n c dng ty trngvi, giy v ty u cc h rc, cng rnh, cc gy dch bnh. Do c kh nngtc dng vi cc cht hu c, nn clorua vi cn c dng ha gii cc cht c

trong chin tranh ha hc. Clorua vi cn c dng trong qu trnh tinh ch dum. Clorua vi c to ra khi cho kh clo tc dng vi vi sa (huyn ph cCa(OH)2 trong nc) theo phn ng:

ClCl2 + Ca(OH)2 Ca + H2O

O Cl

Khi cho clorua vi tc dng vi axit clohiric th c to kh clo:

-1 +1 0

CaOCl2 + 2HCl Cl2 + CaCl2 + H2O

Di tc dng ca nh sng hoc un nng dung dch clorua vi, c mt ng oxithoc st oxit lm xc tc, th c s phn hy clorua vi to kh oxi v canxiclorua.

-2 +1 -1 0

2CaOCl2 s (t0) CuO (Fe2O3) CaCl2 + O2

C th dng hai phn ng trn iu ch kh clo v oxi trong phng th nghim.


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Khi trong khng kh, clorua vi tc dng vi kh cacbonic c trong khng kh vgii phng kh iclo oxit (Cl2O). Kh Cl2O c mi ging kh clo (Cl2). iu nygii thch nguyn nhn clorua vi c mi kh clo.

2CaOCl2 + CO2 CaCl2 + CaCO3 + Cl2O

Trong cng nghip, ngi ta iu ch clorua vi bng cch cho kh clo tc dng vivi ti kh. Clorua vir tin hn, cha hm lng hipoclorit cao hn, d boqun v chuyn chhn so vi nc Javel.

Cl2 + Ca(OH)2 CaOCl2 + H2O

L.5. Khi ha tan kh clo (Cl2) trong nc, th c mt phn clo tc dng vi nc, to

hn hp axit clohiric (HCl) v axit hipoclor(HClO)0 -1 +1

Cl2 + H2O HCl + HClOClo Axit clohiric Axit hipoclor(Cht oxi ha, Cht kh; Cht t oxi ha t kh) (Phn ng oxi ha kh ni phn t)

Phn ng trn ca Cl2 gii thch s lm i mu giy qu xanh t ha cakh clo, ri giy qu b mt mu. Nguyn nhn l axit HCl lm giy qu xanh,cn axit HClO th li lm mt mu giy qu (do tnh oxi ha mnh ca HClO).y l hin tng c trng nhn bit kh clo (Cl2).

Axit hipoclorch tn ti trong dung dch, n km bn, ngay c trong dung dchlong HClO, c s phn hy to kh oxi v axit HCl. S phn hy ny xy racng nhanh di tc dng ca nh sng mt tri. V th nc clo sau mt thigian s mt mu vng nht v ch cn cha a xit clohiric (HCl).

2HClO as 2HCl + O2Axit hipoclor Axit clohiric Oxi

L.6. Iot (I2) tc dng d dng vi dung dch Na2S2O3 (Natri tiosunfat, Natri hiposunfit)to mui NaI v Na2S4O6 (Natri tetrationat). Dung dch Na2S2O3 lm mt muvng ca dung dch iot. Ngi ta thng dng phn ng ny nh phn dung

dch Na2S2O3 bng dung dch I2 (nhm xc nh nng dung dch Na2S2O3 khibit nng dung dch I2 hoc ngc li). Sau khi phn ng va , mt git ddung dch I2 lm cho dung dch phn ng c mu vng rt nht (Hoc mt lngdung dch I2 c d s lm cho dung dch h tinh bt long c mu xanh dng, do cho vo dung dch phn ng trc ). Nhcc hin tng c trng ny mngi ta mi bit phn ng xong (git d dung dch I2 coi nh sai s trong snh phn, hay trong php chun th tch).

+2 0 +2,5 -1

2Na2S2O3 + I2 Na2S4O6 + 2NaI Natri hiposunfit Iot Natri tetrationat Natri ioua



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I.8. Ozon (O3)

[Th hnh l hin tng mt nguyn t ha hc hin din di cc dng n chtkhc nhau. Th d: O2 (oxi), O3 (ozon) l hai cht th hnh ca nguyn t oxi; Cacbongraphit (than ch), Cacbon kim cng), Cacbon v nh hnh (m hng, l ngh) l bacht th hnh ca nguyn t cacbon; Photpho trng (P4), Photpho (photpho tm),Photpho en l ba cht th hnh ca nguyn t photpho]

Ozon (O3) l mt cht th hnh vi oxi (O2). Ozon hin din dng kh iu kin thng,c mu xanh da tri nht, c mi xc. Ozon c tnh oxi ha mnh hn oxi, n ph hycc cht hu c, oxi ho nhiu kim loi, trong c bc.

Ozon c tnh oxi ha mnh l do n khng bn, d b phn hy to thnh oxi nguyn t

(O) [O nguyn t c tnh oxi ha mnh hn oxi phn t, O2, v khng cn cung cp nnglng ct t lin kt i gia O vi O, O=O, trong phn t O2]:

O3 O2 + OOzon Oxi Oxi nguyn t

- Ozon y c iot (iod) ra khi dung dch kali ioua (iodur kalium) (O2 khng ctnh cht ny). Do dung dch KI c dng nhn bit ozon (Nu l ozon th khicho tc dng vi dung dch KI s thu c I2, lm cho dung dch c mu vng, hay I2to ra lm xanh h tinh bt). Hay giy tm dung dch KI v h tinh bt (giy ioua -tinh bt) chuyn ngay sang mu xanh nu c hin din ozon trong khng kh.

KI + O2 + H2O

-1 0 0 -2

2KI + O3 + H2O I2 + O2 + KOHKali ioua Ozon Iot Oxi(Cht kh) (Cht oxi ha)

- Ozon oxi ha c kim loi bc (Ag), thy ngn (Hg). Trong khi oxi (O2) khng tcdng vI kim loi bc.

Ag + O2

0 0 +1 -2

2Ag + O3 Ag2O + O2

- Ozon oxi ha mui sunfua thnh mui sunfat, oxi ha amoniac thnh nitrit,nitrat

-2 0 +6 -2

PbS + O3 PbSO4 + O2Ch (II) sunfua Ch (II) sunfat


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Do c tnh oxi ha mnh nn ozon dit c cc vi khun v th ozon c dng dit trng trong nc v kh trng khng kh. Mt lng nh ozon trong khng khs lm cho khng kh trong lnh, c nh hng tt n cth con ngi, nhng nukhng kh cha nhiu ozon s gy ngc. Trong t nhin, ozon c to thnh toxi khi c sm st. cao 10 30 km, ozon c to thnh do tc dng ca tia tngoi mt tri. Nhvy, cc tia t ngoi ca mt tri c hi cho s sng b ngnchng li. Nhng nm gn y, ngi ta pht hin nhng l thng ca tng ozon.y l mt nguy cang c nghin cu khc phc.

I.9. Hiro peoxit (H2O2)

- H2O2 c tnh oxi ha mnh trong c mi trng axit ln mi trng kim. H2O2 oxiha c I- thnh I2, KNO2 thnh KNO3, sunfua thnh sunfat. H2O2 b khtoH2O.

-1 -1 -2 0

H2O2 + H2SO4 + 2KI 2H2O + I2 + K2SO4(Cht oxi ha) (Cht kh)

-1 -2 -2 +6

4H2O2 + PbS 4H2O + PbSO4Hiro peoxit Ch (II) sunfua Nc Ch (II) sunfat


+3 -1 +5 -2

KNO2 + H2O2 KNO3 + H2OKali nit rit Hiro peoxit Kali nitrat Nc


- H2O2 rt tinh khit tng i bn, nhng n d b phn tch to O2 v H2O khi cln tp cht kim loi nng hay hp cht cc kim loi ny, hoc khi un nng hay bchiu sng. Do bo qun H2O2, ngi ta cht ny trong cc chai thy tinhsm mu cng nh ni ti v rm mt. Ngi ta thy O2c to ra t phn tH2O2 ch khng phi ca H2O. Do lin kt gia O O trong H2O2 khng btm l anion [O - O]2- mt in t. Tt c cc ng dng thc t ca H2O2u da votnh khng bn v tnh oxi ha mnh ca n. Dung dch H2O2 3% c dng sttrng trong y hc, nh sc ming, ra vt thng. H2O2 cng c dng lm cht

ty trng vi, len, la, bng, rm r, giy, my tre,u im ca cht ty H2O2 lkhi dng dung dch thch h p, nng khng ln, n ch lm trng cht c munhng khng lm h hng vt c ty. Cc cht d chy nh giy, mt ca, sbc chy khi tip xc dung dch H2O2 c nng ln hn 65%. Dung dch H2O2mc (ln hn 80%) c dng lm cht oxi ha nhin liu cho cc ng cphn lc.Do tnh d b phn hy ca n, H2O2 cn c dng lm cht to bt cho cc ngnhsn xut vt liu xp.

H2O2 )( 0tas

2

1O2 + H2O

Hiro peoxit Oxi Nc


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- Peoxit (-O-O-) coi nhl mui ca axit H2O2. Do khi cho cc H2O2 tc dng

vi dung dch kim mnh (nh NaOH, KOH, Ca(OH)2, Ba(OH)2) s to peoxit kimloi tng ng v nc; Cn khi cho peoxit kim loi tc dng vi axit th hiro peoxitby ra khi peoxit kim loi. (Axit mnh y c axit yu hn ra khi mui. H2O2c tnh axit mnh hn nc, nhng yu hn nhiu so vi cc axit thng thng khc)

H2O2 + Ba(OH)2 BaO2 + 2H2OHiro peoxit Bari hiroxit Bari peoxit Nc

BaO2 + H2SO4 H2O2 + BaSO4Bari peoxit Axit sunfuric Hiro peoxit Bari sunfat

H2O2 + 2NaOH Na2O2 + 2H2O

K2O2 + 2HCl H2O2 + 2KClKali peoxit Axit clohiric Hiro peoxit Kali clorua

I.10. Oxit kim loi (Oxid kim lai)

Oxit kim loib kh to kim loi tng ng hay oxit kim loi trong kim loi cs oxi ha thp hn. Cc cht kh thng dng kh oxit kim loi nhit caol Al, H2, CO, C. Tuy nhin bn cht kh ny ch khc cc oxit kim loi trong kim loi ng sau nhm trong dy thin ha. Cc oxit kim loi Al, Mg, kimloi kim, kim th, ch b kh to kim loi tng ng ti catot bnh in phn khiin phn nng chy cc oxit kim loi tng ng trn.

K Ca Na Mg Al Mn Zn Cr Fe Ni Sn Pb H Cu Ag Hg Pt Au

+3 0 0 +3

Fe2O3 + 2Al 0t 2Fe + Al2O3


+2 0 0 +1

CuO + H2 0t Cu + H2O


+1 +2 0 +4

Ag2O + CO 0t 2Ag + CO2


+2 0 0 +2

ZnO + C 0t Zn + CO



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+3 +2 +8/3 +4

3Fe2O3 + CO 0t 2Fe3O4 + CO2

St (III) oxit Cacbon oxit St t oxit Cacbon ioxit


+8/3 +2 +2 +4

Fe3O4 + CO 0t 3FeO + CO2

St t oxit Cacbon oxit St (II) oxit Kh cacbonic(Cht oxi ha) (Cht kh)

+2 +2 0 +4

FeO + CO 0t Fe + CO2


+2 0 0 +2

PbO + C C01400 Pb + CO

Ch (II) oxit Cacbon Ch Cacbon oxit(Cht oxi ha) (Cht kh)

MgO + Al 0t

Al2O3 + H2 0t

K2O + CO 0t

CaO + H2 0

t

Na2O + C 0t

Al2O3 Dpnc 2Al + 3/2O2

Nhm oxit Nhm Oxi(Catot) (Anot)

I.11. Mt s phi kim (Khng kim loi) (nh halogen X2, O2, S, N2, P, C, Si, H2)

- Cc phi kim oxi ha kim loi to oxit kim loi hay mui ca kim loi tng ng.

Cn phi kim b kh to thnh hp cht ca phi kim (oxit hay mui) trong phi kimc s oxi ha m.

Th d:

0 0 +3 -1

Fe + 3/2Cl2 0t FeCl3

St Clo St (III) clorua(Cht kh) (Cht oxi ha)


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0 0 +2 2

Fe + S 0t FeS

St Lu hunh St (II) sunfua


0 0 +8/3 -2

3Fe + 2O2 0t Fe3O4

St Oxi St t oxit(Cht kh) (Cht oxi ha)

Nhm t bc chy khi tip xc vi cc halogen X2, mc mnh lit phn ng gimdnt F2n I2.

Al + 3/2Cl2 AlCl3

Nhm Clo Nhm clorua

2Al + 3/2O2 0t Al2O3

2Al + 3S 0t Al2S3

Nhm Lu hunh Nhm sunfua

Cu + 1/2O2 0t CuO

Cu + Br2 0t CuBr2

Au + 3/2Cl2 0t AuCl3

Vng Clo Vng (III) clorua

Ag + 1/2Cl2 0t AgCl

Bc Clo Bc clorua

Li (lng) + 1/2H2(kh) t0 cao; p sut H2 cao LiHLiti Hiro Liti hirua

Na(lng) + 1/2H2(kh) pt ,0 NaH

Natri hirua

3Li + 1/2N2 0t Li3N

Liti Nit Liti nitrua

3Mg + N2 0t Mg3N2

Magie Nit Magie nitrua

Ca(nng chy) + H2 0t CaH2

Can xi Hiro Canxi hirua


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3Ba + N2 0t Ba3N2

Bari Nit Bari nitrua

3Ca + 2P 0t Ca3P2

Canxi Photpho Canxi photphua

Ca + 2C 0t CaC2

Can xi Cacbon Canxi cacbua

4Al + 3C 0t Al4C3

Nhm Cacbon Nhm cacbua

2Ca + Si 0t Ca2Si

Canxi Silic Canxi silixua

2Mg + Si 0t Mg2Si

Magie Silic Magie silixua

Hg + S HgSThy ngn Lu hunh Thy ngn (II) sunfua

Thy ngn tc dng vi lu hunh nhit thng, v vy ngi ta thng dng bt lu hunh gomnhng ht rt nh ca thy ngn ri vi trn nn nh, trnh c tc dng c hi ca thy ngn bay hito ra.

2Cr + 3Cl2 0t 2CrCl3

Crom Clo Crom (III) clorua

2Cr + 3S 0t Cr2S3

Crom Lu hunh Crom (III) sunfua

2Cr + N2 0t 2CrN

Crom Nit Crom (III) nitrua

- Phi kim mnh c thoxi ha phi kim yu hn.

Th d:0 0 +5 -2

2P + 5/2O2(d) C060 P2O5

Photpho Oxi Photpho (V) oxit; Anhirit photphoric(Cht kh) (Cht oxi ha)

0 0 +3 -2

2P + 3/2O2(thiu) C060 P2O3

Photpho Oxi Photpho (III) oxit; Anhirit photphor


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0 0 +3 -1

P + 3/2Cl2(thiu) PCl3Photpho Clo Photpho triclorua(Cht kh) (Cht oxi ha)

0 0 +5 1

P + 5/2Cl2(d) PCl5Photpho Clo Photpho pentaclorua


0 0 -3 +1

P + 3/2H2 C0300 PH3

Photpho Hiro Photphin; Photphua hiro(Cht kh) (Cht oxi ha)

0 0 +1 -2

H2 + 1/2O2 H2OHiro Oxi Nc; Hiro oxit


0 0 -3 +1

N2 + 3H2 Fe, t0, p 2NH3Nit Hiro Amoniac; Hiro nitrua


0 0 -4 +1

C + 2H2 CNi0

500, CH4Cacbon Hiro Metan(Cht oxi ha) (Cht kh)

0 0 +1 -2

S + H2 0t H2S

Lu hunh Hiro Hiro sunfua(Cht oxi ha) (Cht kh)

0 0 +5 -2

5S + 2P 0tt P2S5

Lu hunh Photpho iphotpho pentasunfua(Cht oxi ha) (Cht kh)

0 0 +4 -2

S + O2 0t SO2

Lu hunh Oxi Lu hunh (IV) oxit; Anhirit sunfuar; Kh sunfuar(Cht kh) (Cht oxi ha)

0 0 +2 -2

N2 + O2 30000C (Tia la in) 2NONit Oxi Nitoxit



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204

0 0 +4 1

Si + 2F2 SiF4 (Phn ng xy ra nhit thng)Silic Flo; Fluor Tetraflo silan; Silic tetraclorua


0 0 +4 2

Si + O2 0t SiO2

Silic Oxi Silic oxit; Anhirit silicic(Cht kh) (Cht oxi ha)

0 0 +4 1

Si + 2Cl2 0t SiCl4

Silic Clo Silic tetraclorua; Tetraclo silan(Cht kh) (Cht oxi ha)

0 0 +6 -1

S + 3F2 SF6Lu hunh Flo Florua lu hunh (VI); Hexaflorua lu hunh


- Phi kim mnh (nhF2, Cl2, O2) oxi ha c cc hp cht ca phi kim hay kimloi c s oxi ha trung gian cng cc hp cht ca phi kim c s oxi ha thpnht nh CO, NO, SO2, Na2S2O3, FeS2, FeCl2, FeSO4, FeO, Fe3O4, FeS, NH3, H2S,PH3, KI, KBr, CH4,.

Th d: +2 0 +4 -2

2CO + O2 0t 2CO2

Cacbon oxit Oxi Cacbon ioxit(Cht kh) (Cht oxi ha)

+2 0 +4 -2

2NO + O2 2NO2Nitoxit Oxi Nitioxit


+2 0 +4 -1

CO + Cl2 asC,

COCl2Cacbon oxit Oxi Photgen (Cht c chin tranh)(Cht kh) (Cht oxi ha)

+4 0 +6 -2

2SO2 + O2 V2O5(Pt),4500C 2SO3Anhirit sunfuna r Anhirit sunfuric

(Cht kh) (Cht oxi ha)+2 0 +2,5 -1

2Na2S2O3 + I2 Na2S4O6 + 2NaI Natri tiosunfat; Natri hiposunfit Iot Natri tetrationat Natri ioua



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Gio khoa ha v c Bin son: V Hng Thi205

+2 1 0 +3 -2 +4 -2

2FeS2 + 11/2O2 0t Fe2O3 + 4SO2

Pi rit st; St (II) pesunfua Oxi St (III) oxit Kh sunfur(Cht kh) (Cht oxi ha)

+2 0 +3 -1

FeCl2 + 1/2Cl2 FeCl3St (II) clorua Clo St (III) clorua(Cht kh) (Cht oxi ha)

+2 0 +3 -1

3FeSO4 + 3/2Cl2 Fe2(SO4)3 + FeCl3(Cht kh) (Cht oxi ha)

+2 0 +3 2

2FeO + 1/2O2 0t Fe2O3


+2 0 +3 -2

2Fe(OH)2 + 1/2O2 + H2O 2Fe(OH)3St (II) hiroxit Oxi Hi nc St (III) hiroxit

(Cht rn trng hi lc nht) (Khng kh) (Cht rn mu nu )

+2 2 0 +3 -2 +4 -2

2FeS + 7/2O2 0t Fe2O3 + 2SO2

St (II) sunfua Oxi St (III) oxit Kh sunfur-3 0 0 2

2NH3 + 3/2O2 0t N2 + 3H2O

Amoniac Oxi Nit Hi nc

-3 0 + -2 -2

2NH3 + 5/2O2 0,tPt 2NO + 3H2O

Amoniac Oxi Nitoxit Hi nc

-2 0 0 -2

H2S + 1/2O2(thiu, chy chm) 0t S + H2O

-2 0 +4 -2 -2

H2S + 3/2O2(d, chy nhanh) 0t SO2 + H2O

-2 0 0 -1

H2O + F2 1/2O2 + 2HF(Cht kh) (Cht oxi ha)

cac-phan-ung-oxi-hoa-khu-thuong-gap-trong chuong trinh pho thong

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