10. , 20,0 0,1 NaOH 16,0 0,08 HCl.
. , :
NaOH + HCl = NaCl + H2O
, , :
n 0(NaOH) = 20,0 ∙ 103 ∙ 0,1 = 2,0 ∙ 103 ;
n 0(HCl) = 16,0 ∙ 103 ∙ 0,08 = 1,28 ∙ 103 .
n 0(NaOH) > n 0(HCl), NaOH , , NaOH NaCl :
n 1(NaOH) = n 0(NaOH) n 0(HCl) = 2,0 ∙ 103 1,28 ∙ 103 =
= 0,72 ∙ 103 .
n 1(NaCl) = n 0(HCl) = 1,28 ∙ 103 .
NaCl pH .
(V) 20,0 + 16,0 = 36,0 .
NaOH :
(NaOH) = 0,72 ∙ 103/ 36 ∙ 103 = 0,02 /.
, (3.8) :
pH = 14 + lg C (NaOH) = 14 + lg(0,02) = 12,3
11. , 20,0 0,1 NaOH 36,0 0,08 HCl.
. , :
NaOH + HCl = NaCl + H2O
, , :
n 0(NaOH) = 20,0 ∙ 103 ∙ 0,1 = 2,0 ∙ 103 ;
n 0(HCl) = 36,0 ∙ 103 ∙ 0,08 = 2,88 ∙ 103 .
n 0(NaOH) < n 0(HCl), HCl , , HCl NaCl :
n 1(HCl) = n 0(HCl) n 0(NaOH) = 2,88 ∙ 103 2,0 ∙ 103 =
= 0,88 ∙ 103
n 1(NaCl) = n 0(NaOH) = 2,0 ∙ 103
NaCl pH .
(V) 20,0 + 36,0 = 56,0 .
HCl :
(HCl) = 0,88 ∙ 103/ 56 ∙ 103 = 0,0157 /.
, (3.3) :
pH = lg C (HCl) = lg(0,0157) = 1,8.
12. , 20,0 0,12 NaCN 15,0 0,09 HCl.
. , :
NaCN + HCl = HCN + NaCl
, , :
n 0(NaCN) = 20,0 ∙ 103 ∙ 0,12 = 2,4 ∙ 103 ;
n 0(HCl) = 15,0 ∙ 103 ∙ 0,09 = 1,35 ∙ 103 .
n 0(NaCN) > n 0(HCl), NaCN , , NaCN HCN :
|
|
|
n 1(NaCN) = n 0(NaCN) n 0(HCl) = 2,4 ∙ 103 1,35 ∙ 103 =
= 1,05 ∙ 103 ;
n 1(HCN) = n 0(HCl) = 1,35 ∙ 103 .
(V) 20 + 15 = 35 .
:
(NaCN) = 1,05 ∙ 103/ 35 ∙ 103 = 0,03 /;
(HCN) = 1,35 ∙ 103/ 35 ∙ 103 = 0,039 /.
, (3.15) :
pH = 
lg[ (HCN) / (NaCN)] = 9,3 lg(0,039 / 0,03) = 9,18
13. , 11,25 0,12 / NaCN 15,0 0,09 / HCl.
. , , :
NaCN + HCl = HCN + NaCl
n (NaCN) = 11,25 ∙ 103 ∙ 0,12 = 1,35 ∙ 103 ;
n (HCl) = 15,0 ∙ 103 ∙ 0,09 = 1,35 ∙ 103 .
n (NaCN) = n (HCl), 1,35 ∙ 103 HCN.
(V) 11,25 + 15,0 = 26,25 .
HCN :
(HCN) = 1,35 ∙ 103/ 26,25 ∙ 103 = 0,051 /.
, (3.5) :
pH = 
lg[ (HCN)] = ∙ 9,3 ∙ lg(0,051) = 5,3
14. , 20,0 0,12 / NaCN 35,0 0,09 / HCl.
. , , :
NaCN + HCl = HCN + NaCl
n 0(NaCN) = 20,0 ∙ 103∙ 0,12 = 2,4 ∙ 103 ;
n 0(HCl) = 35,0 ∙ 103 ∙ 0,09 = 3,15 ∙ 103 .
n 0(HCl) > n 0(NaCN), HCl HCN :
n 1(HCl) = 3,15 ∙ 103 2,4 ∙ 103 = 0,75 ∙ 103 ;
n 1(HCN) = 20,0 ∙ 103 ∙ 0,12 = 2,4 ∙ 103 .
HCl HCN, .
(V) 20,0 + 35,0 = 55,0 .
HCl :
(HCl) = 0,75 ∙ 103/ 55,0 ∙ 103 = 0,014 /.
, (3.3) :
pH = lg[(HCl)] = lg(0,014) = 1,87.
15. , 10,0 0,1 / Na2HAsO4 16,0 0,1 / HCl.
. :
Na2HAsO4 + HCl = NaH2AsO4 + NaCl (3.16)
NaH2AsO4 + HCl = H3AsO4 + NaCl (3.17)
:
n (Na2HAsO4) = 10,0 ∙ 103 ∙ 0,1 = 1,0 ∙ 103 ;
n (HCl) = 16,0 ∙ 103 ∙ 0,1 = 1,6 ∙ 103 .
Na2HAsO4 , HCl (3.16), (3.16) 1,0 ∙ 103 NaH2AsO4
(1,6 1,0) ∙ 103 = 0,6 ∙ 103 HCl. (3.17) H3AsO4 NaH2AsO4 :
|
|
|
n (NaH2AsO4) = 1,0 ∙ 103 0,6 ∙ 103 = 0,4 ∙ 103 ;
n (H3AsO4) = 0,6 ∙ 103 .
(V) 10 + 16 = 26 , 26 ∙ 103 .
:
(NaH2AsO4) = 0,4 ∙ 103/ 26 ∙ 103 = 0,015 /;
(H3AsO4) = 0,6 ∙ 103/ 26 ∙ 103 = 0,023 /.
, (3.15) :
pH = 
lg( (H3AsO4) / (NaH2AsO4)) =
= 2,22 lg(0,023/0,015) = 2,03.
