.
,
, . , , , ( ). .
: 1) , 2) , 3) .
I
:
) ;
) , , .
- , , , , .
n 0 , n . , = n . / n 0, , , n . = a × n 0.
, 0 /, = . [/] / 0 [/], . = a × 0.
0 1 0% % 100%:
1) =0, n . = 0 ,
2) =1, n .= n 0 ( >30%),
3) 0, n . << n 0 ( <3%).
( =1 1):
1) ,
2) () KOH, NaOH, CsOH, Ba(OH)2, Ca(OH)2, Sr(OH)2, LiOH ;
3) HNO3, HCl, HBr, HI, HClO4, HClO3, H2SO4 .
( 0):
1) HNO2, HClO, HCN, HF, H2CO3, H2S, H2SO3, H2SiO3, H3PO4;
2) , , , ;
3) (NH4OH), , Cu(OH)2, Fe(OH)3, Zn(OH)2, Al(OH)3 ;
4) .
( = 1, = 0):
AB Az+ + Bz-
0 | - | - | |
[Az+] = 0 | [Bz-] = 0 |
: a) HCl H+ + Cl-
: 0 - -
: 0 0 0
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) H2SO4 2H+ + SO42-
: 0 - -
: 0 (H+) = 20 (SO42-) = 0
) Al2(SO4)3 2 Al3+ + 3 SO42-
0 0 0
0 (Al3+) = 20 (SO42-) = 30
(α 0, . = a × 0):
) - 0, 0 < a << 1; . = a0 ,
Û + +
0 / ½ ½
[HX] = 0 . = ½[H+] = = ½ [X] = =
= 0 - [H+] = ½ = a 0 ½ = a 0
= 0 (1 a)
[] , 25 0:
= ,
, , 0 [H+] 0, 0 >> = [H+]. , < 103, 0 > 0,001 /, [H+].
C , , : = ,
, a [H+] = [X] = a0 = .
, , , (25 0) 0 . , .
, , , , : I H2S ↔ H+ + HS Ka1 = 1,1∙107
II HS ↔ H+ + S2 Ka2 = 3,63∙1012
. , , . .
, , NH4OH:
NH4OH NH4+ + OH
a [OH-] = [NH4+] = a × c0 = ,
c0 , b - .
, ( ) ( ). , , , . . .
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: H2O ↔ H+ + OH-,
:
= [H+] [OH-] = K × [H2O] = Kw,
W = 1014 . , ( ) pH = - lg [H+] ( ) pOH = - lg [OH-]. (-1) :
pH + pOH = 14.
, H+ OH- , , , .
pH , pOH = 14 pH, :
[H+] = 10-pH, a [OH-] = 10-pOH = 10 pH 14.
H+ OH- :
1) , [H+] = [OH] = = 10-7 /,
pH = pOH = 7.
2) , [H+] > [OH], 0 < pH < 7.
3) , [H+] < [OH], 7 < pH < 14.
II
, , H+ OH- .
pH , , .
, , pH , .
) ( FeCl3):
- : FeCl3 Fe3+ + 3 l,
Fe3+
I - : Fe3+ + H2O ↔ FeOH2+ + H+, pH < 7
II :: FeOH2+ + H2O ↔ Fe(OH)2+ + H+
III :: Fe(OH)2+ + H2O ↔ Fe(OH)3↓ + H+
, .
) ( Na3PO4):
- : Na3PO4 → 3Na+ + PO43,
PO43
I : PO43 + H2O ↔ HPO42 + OH, pH > 7
II : HPO42 + H2O ↔ H2PO4 + OH
III : H2PO4 + H2O ↔ H3PO4 + OH
, .
pH . ( ) , :
w = 1014 (b ) , .
. :
H3PO4 → H2PO4 → HPO42 → PO43
K1 K2 K3
, .
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PO43 : PO43- → HPO42- → H2PO4- → H3PO4.
K1 = w / 3; K2 = w / 2; K3 = w / 1.
pH , , 0 /.
Na3PO4 → 3Na+ + PO43
0 30 0
PO43 h1 (h1<<1), . (PO43) = h1 0
PO43 + H2O ↔ HPO42 + OH
0 / ½ ê - ½ -
[PO43-] = 0 . = ½ ê [HPO42-] = h1 0 ½ [OH] = h1 0
= 0 (1 h1)
PO43 , 1 = ,
h1 = , [OH] = h1 0 = pOH = - lg (),
pH = 14 pOH.
, (1 << h1) , < 103, 0 > 0,001 /; .
, . , , , , .
Na2HPO4 → 2 Na+ + HPO42, HPO42
) III HPO42 ↔ PO43 + + 3(34) = 1,261012
) HPO42 + H2O ↔ H2PO4 + OH = w / 2(34) =
= 1014 / 6,34108 = 1,57107. , HPO42 .
H3PO4 | NaH2PO4 | Na2HPO4 | Na3PO4 | |
23 | NaHCO3 | Na2CO3 | |
III
, . nBm S, / , . , (nBm). , , 25 0.
nBm S, (a = 1),
nBm () Û nBm (. -) n z+ () + m Bz-()
S / [z+] = nS ½ [Bz-] = mS
:
(nBm) = [z+]n [Bz-]m = (nS)n(mS)m = nnmmSn+m
, nBm
S = , /,
nBm ρ = S × M(nBm), /.
. Ca3(PO4)2
Ca3(PO4)2() Û Ca3(PO4)2(. ) 3 a2+() + 2 PO43 ().
S / [Ca2+] = 3S ê [PO43-] = 2S
(Ca3(PO4)2) = 2,0 ×10-29, :
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(3(PO4)2) = [Ca2+]3× [PO43-]2 = (3S)3× (2S)2 = 108 × S5,
S = = 7,13 ×107 /
ρ = S × M(3(PO4)2) = 7,13 × 107 × 310 = 2,21 × 104 /,
[Ca2+] = 3S = 3 ×7,13 × 107 = 2,139 ×106 /,
[PO43-] = 2S = 2 ×7,13 ×107 = 1,426 ×106 /.
, . , , . .
. 1) , , , , + :
3() Û 3(. ) 3 a2+() + 2 O32 ().
O32 (. ) + 2 +() → 23 → 2↑ + 2
, S4 ?
2) Al(OH)3 , , Al3+ :
Al(OH)3 () Û Al(OH)3 (. ) → Al3+() + 3 ()
Al3+() + 4 () → [Al(OH)4]()
() + +() → 2
, , , . 3(PO4)2 , : ) 0,1 / ) 0,1 /:
) 3(PO4)2 S* ( S* << S) Ca2+ PO43- :
Ca3(PO4)2() Û Ca3(PO4)2(.) 3 a2+() + 2 PO43 ().
: S* / [Ca2+]* = 3S* ê [PO43]* = 2S*
CaCl2 Ca2+ + 2 Cl
0,1 / 0,1 / 0,2 /.
, [Ca2+ ] = [Ca2+]* + 0,1 0,1 /, [Ca2+]* << 0,1 /, [PO43-] = [PO43-]* = 2S* . :
(3(PO4)2) = [Ca2+]3[PO43-]2 = (0,1)3× (2S*)2 = 4×10-3 × S*2,
S* = = 7,07×10-14 / << S = 7,13 ×107 /.
) 3(PO4)2 S* ( S* << S) Ca2+ PO43- :
Ca3(PO4)2() Û Ca3(PO4)2() 3 a2+() + 2 PO43- ().
: S* / [Ca2+]* = 3S* ê [PO43-]* = 2S*
Na3PO4 3 Na+ + PO43-
0,1 / 0,3 / 0,1 /.
, [PO43-] = [PO43-]* + 0,1 0,1 /, [PO43-]* << 0,1 /, [Ca2+ ] = [Ca2+]* = 3S* :
(3(PO4)2) = [Ca2+]3× [PO43-]2 = (3S*)3 × 0,12 = 0,27×S*3,
S* = = 4,2×10-10 / << S = 7,13 ×107 /.
: , ; .
1) 1 2 1 2.
2) 1.
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3) , , 0,5.
4) 0,05. , . (). 1,68; 4,01; 6,86 9,18, 0 14.
50 25 . , , , 1.
1 ,
(c = 0,1/3) | , | ||||
HCl | |||||
CH3COOH | |||||
FeCl3 | |||||
NH4Cl | |||||
NaCl | |||||
Na2SO4 | |||||
CH3COONa | |||||
NH4OH | |||||
NaCO3 | |||||
Na2CO3 | |||||
NaOH |
. : (CH3COOH) = 1,754105; 3(Fe(OH)3) = 1,351012; (NH4OH) = 1,77105; 1(2CO3) = 4,45107 ; 2(2CO3) = 4,691011
2 -
HInd | Ind | ||
3,1 4,0 | < 3,1 | > 4,0 | |
8,2 10,0 - | < 8,2 | > 10,0 |