. . , , , . , -, , , . (. 4.2), ( 4.5), ( 6.3), ( 7.2). - . :
- , ;
, , , ;
( ) ;
, - , .
- , , .
. - , . XVIIXIX , - (. , .. , . , . -, . , .. ). :
(. , . ),
(. , . ),
(. ).
, , , , +, , . ( ), + (), , . --
, .
, , , , . . , , , , ; . . , , , 3 , . , - . .
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, XIX , . ( N). , . , --
, . ( ) - . - , .
. , , . --
[1]. . , .
. ( 1923 .) . () . (), , : . : - , . . . . , , .
, , . () (B) , . :
: 3H + NH3 Æ3 + NH4+ .
, - . , .
, . . . . , . + . , , H3O+ , 3H2+ . . , , (. ). - .
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, . , , . . :
HCl + H2O Cl + H3O+ .
, (), , , HCl . , :
HCl + 3 ÆCl + 3H2+ .
.
, - ; , , , , . - , , . : , . , .
, , . , ( ) Cl Cl. , . NaCl -, ( ). 3 HCl , Cl , .
. , (3H) (NH3), , . (3) (NH2) .
: , . . , . , , , , , . . , - , -. , - - , (, ) .
. . . :
, , ( e) . , , 66, Cl4, CS2 .;
(), , ( 3H, H );
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(), , ( H2N(2)2NH2 , , , );
, ().
, :
, ( 55N);
() (e > 15), . - . : (3)2, (3)2N, (3)2S, 3N.
, (, ), HL . :
HL + HL ÆH2L+ + L.
(H2L+) (L). HL, :
HL = a H2L+ a L ≈ [H2L+] [L]. (3.13)
, . , (. 3.2). () . , pH = lg [H+], = lgK, HL= lg HL.
3.2
HL | e | |||
2 | 14,0 | |||
25OH | 19,0 | 24,3 | ||
() | (3)3OH | 24,5 | 10,9 | |
(.) | 3H | 14,4 | 6,2 | |
H2N(2)2NH2 | 15,3 | 12,5 | ||
3N | 33,3 | 38,0 |
,
H2O + H2O ÆH3O+ + ,
w = a H3O+ a OH= 1,0 ∙1014, w = 14,00 ( 25). ; . , - :
w = [H3O+][OH]. (3.14)
. ().
= lg a H3O+. (3.15)
, a H3O+≈ [H3O+], : = lg [H3O+]. :
= lg [H2L+]. (3.16)
, (. 6.1.2). , , . , , pH .
(, ) . , ; , , , ; .
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, , [H2L+] = [L] = . : = HL / 2. , . [H3O+] = [OH] = = 1,0 ∙107 /, = pKw2= 7,00 ( 298 ). ( ). [H2L+] > , < HL/2. [H3O+] > < 7. , , H > HL/2, , > 7.
, 1 , . . , 0 HL. , 298 1 ( ) = 0, 1 = 14.
. 3.3. ()
()
, HL , . , 100 w = 12,26, 7,00, 6,13.
. , = 9,5 , ( HL = 19) , ( HL = 24,5) . , , . ( ) .
. :
, ;
;
( 100 %);
;
. , > 105 .
() H3O+ . , [H3O+] = ,
= lg = . (3.17)
(N 3N) [OH] =
[H3O+] = = = , = 14 . (3.18)
(3.18) :
= HL . (3.19)
3.1. 5103 .
. , + . (3.18):
= 14 + lg(5103) = 11,7.
(3.173.19) H3O+ , . (< 105 ) . , (3.17) , 109 HCl = 9, . . ! , , (3.15) H3O+. (H2SO4, ()2 .) .
. ( ) H :
H + H2O Æ + H3O+;
K = . (3.20)
H , , . (3.20) , . - (, ), /. . 2025 . , , . , , , p , , .
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, , . , = 1 = 0. ( HAc) p Ka = 4,76, p Ka = 9,24 . . K .
+ H2O Æ + OH. Kb:
Kb = . (3.21)
, Kb Kb. , , -, Kb = 1 Kb = 0.
; , (3.20) (3.21). :
K Kb = w K + Kb = 14. (3.22)
, :
K Kb = HL K + Kb = HL.(3.22)
K : K, (. 3.4):
. 3.4.
K
(3.22) (3.23) , . , . . , , , . , . :
[Al(H2O)6]3+ + H2O Æ[AlOH(H2O)5]2+ + H3O+
( Al3+ + H2O Æ[AlOH]2+ + 3O+) .
. .
, . Ki Kbi, . , K 1 > K 2 > K 3, Kb 1 > Kb 2 > Kb 3.
[Al(H2O)6]3+ , , :
[AlOH(H2O)5]2+ + H2O Æ[Al(OH)2(H2O)4]+ + H3O+ .
[Al(OH)6]3.
, , , . . , :
HA + B ÆA + HB.
. :
= .
, . (. 3.20).
a 1= [H3O+]; a 2= [H3O+].
, :
= = .
:
lg = p Ka 2 p Ka 1. (3.23)
, ( ) , .
3.2. :
3 + NH3 Æ3 + NH4+ .
. : /- 1 = 4,76; / 2, = 9,25. (3.23):
lg = 9,25 4,76 = 4,49, = 104,49.
. ( ) .
. ,
S + NH3 ÆS2 + NH4+
, 103,35. , .
. . a t [2]. , . :
a t = = . (3.24)
,
a t = = . (3.25)
, . , , (3.21), :
= [] + []
K = = = . (3.26)
(a t. <<1) (3.26) K = . :
a t= . (3.27)
:
a t= . (3.28)
. .
, (3.24) (3.27):
[H3O+] = a t = ,
= . (3.29)
(3.25) (3.28) :
[OH] = a t =
= p w = 14 . (3.30).
. , , (3.27) (3.29) (3.30), , :
> 102 K , > 102 Kb . (3.31)
, H3O+ , .
3.3. 0,10 0,10 AlCl3.
. ( K = 3,75). pH (3.29). , (3.31). , 0,5 (3,75 + 1,0) = 2,38. , , , H3O+, .
, , . , (3.29), . 1 = 3,0, Al3+ , (3.31). , 0,5 (3,0 + 1,0) ≈ 2,0. AlCl3 , .
, , , .
, . (3.29) (3.30), (. 3.3). ,
K 1< K 2 3 ( ) (3.32)
Kb 1< Kb 2 3 ( ) (3.33)
(. ). .
3.4. 0,010 Na2S.
. S2 ( = 2). :
S2 + H2O ÆS + (1 )
S + H2O Æ2S + (2 )
:
Kb (S2) = 14,00 K 2(2S) = 14,00 12,60 = 1,40
Kb (S) = 14,00 K 1(2S) = 14,00 7,00 = 7,00.
3 , . . (3.33) . , Kb = 0,040. (3.30), = 12,3. , , - , . (3.30) , - , (3.31) . (3.21) [O] = [S]:
Kb (S2) = = .
[O]:
[O]2 + Kb [O] Kb = 0.
:
[O] = = = 8,3∙103 /.
= 14 + lg(8,3∙103) = 11,92.
, (3.31) = 12,3, [O] = 0,02 /.
: 11,92.
, . . , :
+ H2O Æ2 + OH
+ H2O Æ2 + H3O+.
, , , :
[H3O+] = , (3.34)
. (3.35)
1, 2 H2A/HA HA/A, , . (3.35) , ( , ). . 8,34, ( 1 = 6,35, 2 = 10,32).
(3.35) , , , 3NH4, NH4NO2 . . K , .
3.5. 0,1 NH4NO2 .
. NH4+ NO2. , , (3.35). : K (HNO2) = 3,16; K (NH4+) = 14,00 Kb (NH3) = 14,00 4,76 = 9,24. (3.35) = 0,5 ( 1+ 2) = 0,5∙(3,16 + 9,24) = 6,20.
, , . , . . , :
. H3O+ ( ) . :
= lg . (3.36)
:
= 14 + lg . (3.37)
. ( -), .
3.6. , 0,01 HCl 0,05 NO3 .
. . , [H3O+] = 0,01 + 0,05 = 0,06 /. pH = lg 0,06 = 1,2.
. - . () , , . , . , : NH4+ NH3. : H2S, HS S2. - , , .
. . (/), . (3.20) .
K = = .
, a = , a = . : = [A] + [HA]. :
a = = = = ,
a = 1 a = 1 = . (3.38)
( 3 ). , (, ) :
= ,
a = , (3.39)
a = .
() ai (. 3.1, 3.5). . , 23 , . , , . (3.38) , , [H+] >> Ka a ≈ 1, a ≈ 0. , [H+] << Ka, : a ≈ 1, a HA ≈ 0. , . , , << K a ≈ 1. 12 = . 12 , , , (a ≈ 0).
. 3.5. (pKa = 9,24)
, , (. 3.5). (3.38) (3.39) , = K , 0,5. , = K a = 0,5.
= Ki, .
, < p K 1; 1 2 . , . . , , . , , , .
3.7. , (H4P2O7) HP2O73.
. H4R ( ). 1 = 0,91; 2 = 2,10; 3 = 6,70; 4 = 9,32. , , 0,91, H4R, 0,91 2,10 H3R, 2,10 6,70 H2R2, 6,70 9,32 HR3, , > 9,32 R4 . - , . . = 0,5 ∙ (6,70 + 9,32) = 8,01. , , , 273-. , (. 3.6). , HR3 ( 8) 90 %, . . .
. 3.6. :
1 H4R; 2 H3R ; 3 H2R2; 4 HR3; 5 R4
. , . , ( ). , 1 = 7 104 , 4, . . 3 . 104 103 , 11.
, , 10 . , , (3, 3), (NH3, NH4+), (H2PO4, HPO42) . , : , , . : -. () Na2B4O7 102. :
472 + 32 = 2 33 + 22.
( ).
.
, , .
(3.20) :
[H3O+] = K ; = K + lg .
, , , [HA] ≈ C , [A] ≈ C . :
= K + lg . (3.40)
(3.40) ( -
) , . , . 0,1 ≤ ≤ 10, ( K 1). . , K ; , (3.40), ( 3.8).
. (3.40), . , [3]. , , . , , . , (3.40), , ( ):
= K + lg .
n :
= K + lg .
n :
= K + lg .
p :
p = = . (3.41)
() . : , 1 . :
p = 2,3 . (3.42)
(3.42) , ( , ) = , = K. . .
3.8. , 1 0,75 . 1 50 0,2 ?
. (3.40). K (NH4+) = 14,00 Kb (NH3) = 14,00 4,76 = 9,24. () = 0,5 /, = (NH4+) = 2 (NH4)2SO4 = 0,75 /.
= K + lg = 9,24 + lg = 9,07.
1 0,5 NH3 0,75 NH4+. = 0,2 0,05 = 0,01 l. (3.41):
= K + lg = 9,24 + lg = 9,05.
, 0,02 .
3.9. 5,00 1?
. , K 46. , , 3H, 3, K = 4,76. (3.40):
lg = K = 5,00 4,76 = 0,24;
= 100,24 = 1,74; = 1,74 .
p ³ 1, :
p = 2,3 = 2,3 ³ 1; ³ 0,684 /.
(3H) = 0,684 / (3Na) = 0,684 ∙ 1,74 = 1,19 /, , = 1,74. , .
[1] , . (NH4OH) , .
[2] α , , .
[3] ; .