化学第三章酸碱滴定

1、第三章第三章酸碱滴定法酸碱滴定法 酸碱质子HACAc-+H+H2CO3HCO3-+H+HCO3-CO32-+H+NH4+NH3+H+H6Y2+ H5Y+H+NH3OH+NH2OH+H+ (CH2)6N4H+(CH2)6N4+H+NH4+ + H2O H3O+ + NH3 KKHOHsw101014.pHpOH 14KSHSs2水的离子积水的离子积KH OAHAa3KOHHAAbKKKabwKKKabsKKKaaa123321bbbKK. 1WbababaKKKKKKK CHAAHAaaHACHAHAAAHAKHHHK1111AaaACAHAAKHKHAA136. 01

2、00 . 11078. 1100 . 1555HKHaHAc64. 036. 01AcLmolCHAcHAc/036. 036. 01000. 0LmolCAcAc/064. 064. 01000. 0H2C2O4 HC2O4-+ H+ HC2O4- C2O42- + H+ CH C OHC OC O224242421241211224HC OaaaaHC OCKHHKHKK2242122112242C OaaaaaC OCKKHKHKKCOCHOCH422422HHKHKKaaa221120121H3PO4 H2PO4 - + H+ H2PO4- HPO42- + H+ HPO42- PO4

3、3- + H+ OHCOHAHaaCHHKCHwaB + H + BH + H2O H + + OH OHBHHOHKCOHWbbCOHHAOHCKHaW1HCKHKKHaaaWHKKCKaaaa242HC KaaCKaa 500CKKaaW 20CKKaaW 20HCKHKaaaOHKKCKbbbb242OHC KbbHC Kaa11bbKCOH21aaKKH21aaKKHHKKaa23HCCKabaabaCCpKpHlgbaaCCpKpHlg或小结小结aHAKHHAHAHACHAaaAKHKAHAACAHAA1续前aCHbCOHaaKCHOHC KbbHC Kaa11bbKCOH21aaK

4、KHHKKaa23HCCKabaabaCCpKpHlg酸式体 碱式体 或碱式体 酸式体 ee见插图(H3C)2 + NNNHSO3OHH+(H3C)2NSO3NHN甲基橙（MO）红色（醌式）黄色（偶氮式）pKa = 3.4OHOHOHH+pKa = 9.1HOCOOOOCOO羟式（无色）醌式（红色）酚酞（PP）KHInHInKinaKHInHInin HIn H + + In -（续前）KHInHInin aCaHInInHKin KHOHKtw11101014.KAHA OHKKKtbaW1KHAHAKKKtabW1H3O+ + OH- H2O+ H2OKHOHKtw11101014.Lmo

5、lCHa/1000. 00 . 1pHLmolCVVVVHababa/100 . 51 . 098.1900.2098.1900.2053 . 4pHHOHKmolLw 107/0 . 7pHLmolCVVVVOHbbaba/100 . 51 . 002.2000.2000.2002.2053 . 4pOH7 . 9pH 1.0 mol/L NaOH1.0 mol/L HCL pH=3.310.7 选择甲基橙，甲基红，酚酞 0.1mol/Ll NaOH0.1mol/L HCL pH=4.39.7 选择甲基红，酚酞，甲基橙（差） 0.01mol/L NaOH0.01mol/L HCL pH=5.

6、38.7 选择甲基红，酚酞（差）OH- + HA A- + H2OKAHA OHKKKtbaW1反应完全程度不高LmolKCHaa/1034. 11000. 0108 . 13588. 2pHHACACaabaCCpKCCpKpHlglgCmolLHAC20001998200019980100050105./CmolLAC1998200019980100050102./76. 7 pH27. 5pOH73. 8 pH30. 4pOH70. 9 pHLmolCVVVVOHbabab/100 . 51000. 000.2002.2000.2002.205bawbbCKKCKOHLmolCb/050

7、00. 021000. 0 Ka ，酸性，pH Ka10-9时无法准确滴定 C ，pH，滴定准确性差H3O+ + A- HA + H2O KHAHAKKKtabW1反应完全程度不高 H3PO4 H + H2PO4- H2PO4- H + HPO42- HPO42- H + PO43- ）66. 42)(21aapKpKpH94. 92)(32aapKpKpH 溴甲酚绿溴甲酚绿+ +甲基橙甲基橙 酚酞酚酞+ +百里酚酞百里酚酞）CO32- + H+ HCO3- Kb1= 10-3.75HCO3 - + H+ H2CO3 Kb2= 10-7.6237. 82)(21aapKpKpH LmolKCH

8、aa/103 . 104. 0103 . 44719 . 3pH 过程： NaOH HCL / NaCL HCL / - Na2CO3 V1 NaHCO3 V2 H2O+CO2 %1001000)(%21SMVVCNaOHNaOH%1001000221%32232SMVCCONaCONa过程： HCL / ，V1 CO2 + H2ONaOH + Na2CO3 NaOH + BaCO3 BaCL2 V2 HCL / NaCL + H2O%1001000%2SMCVNaOHNaOH%1001000)(21%322132SMVVCCONaCONa%1001000)(%SMVCVCNNNaOHNaOH

9、HCLHCLaNH4+ + OH - NH3+ H2O NH3 + HCL（定过量） NH4CL HCL(过量）+ NaOH NaCL + H2O加热b%1001000%SMVCNNHCLHCL4NH4+ + 6HCHO (CH2)6N4H+ + 3H+ + 6H2O14NaOHNHnn%1001000%SMVCNNNaOHNaOH422)(424NHOHCONHCSOHSOCnmu解：aaCKH由0 . 3pH和510aK510bawbbCKKCKOH所以5pOH9pH解：2102100 . 1102 . 6100 . 1HKHaHCNHCNCN1CNHCN25. 0lg3 . 5lgbabaCCCpKpH由加入前LmolCNaOH/05. 0100401000200. 0已知6 . 5050. 025. 005. 0lg3 . 5bCpH由加入后LmolCb/35. 045. 520.