2005
54
24.1
:
.
: : , 2005, 16.
: .., ..-. .,
.., ...,
, 2005
.
: , .
, , :
H2O ←→ H+ + OH-.
:
[ H+ ] [OH-]
= = 1,86 10 16 (298 ).
[H2O]
, :
[H2O] = 1000/18 = 55,56 /.
, H+ OH -:
[ H+]×[OH -] = ×[H2O] = 1,86 10 16 ×55,56 = 10 14.
[H+]×[OH -] = 1014 = - .
[H+] = [OH -] = 10-14 = 10 7 /.
[H+] > 10 7 /
[OH-] < 10 7 /.
[H+] < 10 -7 /
[OH -] > 10 7 /.
(H)
, , :
pH = - lg[H+].
, H = 7,
H < 7 ([H+] > [OH -]), H > 7 ([H+] < [OH-]).
,
[H+],
/
10 0 10- 2 10 -7 10 -12 10 - 14
pH 0 2 7 12 14
|
|
, (.1).
1
, | ||||
- | 5,0 8,0 8,0 9,8 3,1 3,4 |
. , . 1 13. , .
, , , , . , .
, . , (NaCl,K2SO4, LiNO3, KClO4
.), , , = 7.
, , , . .
.
1. , (NH4Cl, Pb(NO3)2, NH4NO3, CuCl2, NiSO4, BiCl3 .), . , NH4Cl NH4+ Cl-:
NH4Cl NH4+ + Cl-.
Cl- - , HCl. NH4+ NH4OH. :
NH4+ + HOH NH4OH + H+.
, < 7.
NH4Cl + H2O NH4OH + HCl.
: H2O NH4OH. , , , .. .
, ( H2O << NH4OH).
, . . NiSO4, :
NiSO4 Ni2+ + SO42-.
Ni2+ OH-, NiOH+ - . , ,
|
|
Ni2+ + HOH NiOH+ + H+ ( ).
=7 < 7
H+, ( < 7) .
2NiSO4 + 2H2O (NiOH)2SO4 + H2SO4.
, .
NiOH+ + HOH Ni(OH)2 + H+ ( ).
(NiOH)2SO4 + 2H2O 2Ni(OH)2 + H2SO4.
2. ,
(NaCH3COO, NaCN, Na2CO3, K2S, Na2SO3, Ba(CH3COO)2, KNO2 .),
. , :
KNO2 K+ + NO2-.
K+ , KOH. - (NO2-) NO2- + HOH HNO2 + OH-.
- , > 7.
KNO2 + H2O HNO2 + KOH.
, .
: Na2CO3 2Na+ + CO32-.
CO32- + HOH HCO3- + OH-,
pH = 0 pH > 7
Na2CO3 + H2O NaHCO3 + KOH
HCO3- (.. ), H2CO3
, HCO3- , H2CO3:
H2O3 H+ + HCO3- 1 = 3 10 7,
HCO3- H+ + CO32- 2 = 5 10 11.
O32- , -, , :
HCO3- + HOH H2CO3 + OH- ( ),
NaHCO3 + H2O H2CO3 + NaOH.
, - .
3. , (NH4CH3COO, NH4HCO3, Fe(CH3COO)3, (NH4)2S, NH4NO2,
Al2(CO3)3, Al2S3, Cr2S3, CuS .), . :
( )
NH4CH3COO + H2O CH3COOH + NH4OH,
NH4+ + CH3COO - + HOH CH3COOH + NH4OH;
( )
Fe(CH3COO)3 + H2O FeOH(CH3COO)2 + CH3COOH,
Fe3+ + 3CH3COO - FeOH2+ +2CH3COO - + CH3COOH;
( )
(NH4)2S + H2O NH4OH + NH4HS,
2NH4+ + S2- + HOH NH4OH + NH4+ + HS -.
, ,
Al2S3:
l2S3 2Al3+ + 3S2-,
Al3+ + HOH AlOH2+ + H+,
S2- + HOH HS - + OH .
H + OH - , :
2Al3+ + 3S2- + 6HOH 2Al(OH)3 ¯ + 3H2S,
Al2S3 + 6H2O Al(OH)3 + 3H2S.
, . .
, , ( ), ( ), ( ) .