現(xiàn)代基礎(chǔ)化學(xué)：第9章 酸堿和離子平衡

1、波波 義義 耳耳堿堿 阿侖尼烏斯阿侖尼烏斯阿侖尼阿侖尼烏斯烏斯堿堿OH- -OH- -布朗斯特布朗斯特布朗斯特布朗斯特和和劍橋大學(xué)的劍橋大學(xué)的勞萊勞萊同時同時堿堿H3O+H+堿堿Ac- -Ac- -NH3NH3H2PO4- -H2PO4- -HPO42- -HPO42- -H2OH2OOH- -OH- -堿堿(2) 堿堿(1) H2OAc- -NH3Cl- -H2O OH- - NH3OH- -1. 弱酸與弱堿的解離平衡常數(shù)弱酸與弱堿的解離平衡常數(shù)H2OAc- -HAcAcOH3oa KNH3 OH- -NHOHNH3ob 4KOHOH3ow KowK14100 . 1 owKH2O- -SH

2、HSOH23oa1 K- -H2O- -HSSOH3oa2 2KH2OAc- - 2. 共軛酸堿的共軛酸堿的 之間的換算之間的換算oboaKK ，Ac- - OH- -oaKobKH2O OH- - oboaowKKK H2O- - - - H2O- - oa1Koa2K- - - - OH- - - OH- -ob1Kob2Kob2oa1owKKK ob1oa2owKKK owKowoaKcK20 owobKcK20 H2OAc- -xcxK 2HAcAcOH3oa242oaoaoacKKKx 解出：解出：）（條條件件：owoaKcK20 ,500 oaKc如如：oaHcKx cxxcxK2

3、2 oaOHH3OOHoaKobKobOHcK 242obobobOHcKKK %100 弱酸的初始濃度弱酸的初始濃度平衡時解離的弱酸濃度平衡時解離的弱酸濃度H2OAc- -xcxK 2oacx cxc cKoa 解：解：51075. 1 oHAca,K500,20 oaowoaKcKcK且且621011. 724 oaoaoaHcKKK15. 5 lgHpH51032. 1 oaHcK88. 4 pH解：解：51075. 1 oHAca,K88. 2 lgHpH500,20 oaowoaKcKcK且且31032. 1 oaHcK31031. 1 H解：解：owoboaHKKK ,1077.

4、14 oHCOOHa,K51074. 1 oNHb,3K111065. 5 oHCOOHa,owoHCOOb,KKK101075. 5 oNHb,owoNHa,34KKK1-7Lmol103.19H 解：解：H2O- - - - H2O- - 71007. 1 oa1K131026. 1 oa2K500,20 oa1owoa1KcKcK且且1oa1LmolH 41003. 1cK99. 3 pHSHSSOH3oa2 22K1Lmol101.26S 132解：解：-1L0.1molHClH H2O- - 71007. 1 oa1K- - H2O- - 131026. 1 oa2KH2O- - 2

5、01035. 1 oa2oa12223oaSHSOHKKK續(xù)解：續(xù)解：MOHSHS232oa219201035. 101. 01035. 11 . 0 KH2OAc- -解：解：51074. 1 obK1obLmolOH 351032. 11074. 110. 0cK88. 2 pOH12.11 pHH2O + +51074. 11 . 0)2 . 0( xxxKNHOHNH34ob1 . 01 . 0; 2 . 02 . 0 xx近似認為：近似認為：51074. 12 x1Lmol 6107 . 8x06. 5 pOH94. 8 pHH2O1 oapKpH緩沖溶液演示實驗緩沖溶液演示實驗H2

6、OAc- -解：解：1LmolAc 10. 0505020. 0501LmolHAc 10. 0505020. 050HAcAcOH3oa K51075. 1 oa3OHK76. 4 pHHClAc 1Lmol088. 02505050. 0220. 050Ac1LmolHAc 108. 02505050. 0220. 050HAcAcOH3oa K51014. 2088. 0108. 0 oa3OHK續(xù)續(xù) 解：解：67. 4 pHAc Ac 1LmolAc 108. 02505050. 0220. 0501LmolHAc 088. 02505050. 0220. 050HAcAcOH3oa

7、K51043. 1108. 0088. 0 oa3OHK續(xù)續(xù) 解：解：85. 4 pHCH3COOH + OH H2O + CH3COO H2O + CH3COOH H3O+ + CH3COO H3O+CH3COO CH3COOHCH3COO CH3COOHOH CH3COO CH3COOHHAc NaAc 緩沖體系中加入緩沖體系中加入HCl、NaOH 后組分濃度變化后組分濃度變化HA+H2O A- -+H3O+HAAOH3oa KAHAOHoa3-K 堿堿酸酸cclgpKpHoa 酸酸堿堿cclgpKpOHob 酸酸堿堿cclgpKpHob 141oapK13831017. 4,1031.

8、6,1008. 7 oa3oa2oa1KKK解：解：9061002001031682.lg).lg(HPOPOHlgpKlgpKpH442oa2oa2 堿堿酸酸cc,oa2K解：解：酸酸堿堿根據(jù)：根據(jù)：cclgpKpHob 14NH.lg10lg1.74. 95-41001481Lmol.NH02804解解得得：解：解：HAc+NaOH NaAc+H2O510751 .oHAc a,K已已知知：910751.owoHAc a,oKKK此此反反應(yīng)應(yīng)的的續(xù)解：續(xù)解：;.).(.HAc03300100200100201000330010020010100.Ac7640107515.).lg(lgpK

9、pHoa 堿堿酸酸cc1oaowobLmol.OH610353KKccK1Lmol.Ac0500020020020100完完全全反反應(yīng)應(yīng)后后的的738.pH 1Lmol.).(.OH02000500200301003012.pH 0.00 20.00 2.88 18.00 2.00 5.71 19.98 0.02 7.75 20.00 0.00 8.80 20.02 0.02 9.70 22.00 2.00 11.70 40.00 20.00 12.50大自然的溶洞奇觀大自然的溶洞奇觀X 射線胃腸鋇餐造影射線胃腸鋇餐造影X 射線胃腸鋇餐造影射線胃腸鋇餐造影CaF2(s) Ca2+(aq) +

10、2F- -(aq)osp2oFCaKK2為為該該反反應(yīng)應(yīng)的的標(biāo)標(biāo)準(zhǔn)準(zhǔn)平平衡衡常常數(shù)數(shù)ospK對任意一個難溶電解質(zhì)的溶解平衡：對任意一個難溶電解質(zhì)的溶解平衡：AmBn(s) mAn+(aq) + nBm- -(aq)nmmnospBAKAmBn(s) mAn+(aq) + nBm- -(aq)smAnsnBmn)(mnmnmnmmnospnm)n()m(BAsssK相同類型的難溶電解質(zhì)相同類型的難溶電解質(zhì)不同類型的難溶電解質(zhì)不同類型的難溶電解質(zhì)解：解：n)(mnmospnmsK2AgCloAgClsp,sK1oAgClsp,AgClLmol.510341Ks31212124242CrOAgoCr

11、OAgsp,42:n,m,CrOAgsK對對1oCrOAgsp,CrOAgLmol.42425310564KsJospKospKJ ospKJ ospKJ AgCl 沉淀的生成沉淀的生成Ag2CrO4 沉淀的生成沉淀的生成131091 .oMn(OH) sp,2K已已知知：解：解：1oNHb,Lmol.OH3351032110741100cKosp2.).(.OHMnKJ732210741103211001. 判斷沉淀是否完全的標(biāo)準(zhǔn)判斷沉淀是否完全的標(biāo)準(zhǔn)2. 影響沉淀完全的因素影響沉淀完全的因素(1) 同離子效應(yīng)同離子效應(yīng)解：解：1oCrOAgsp,)CrOAg(Lmol.4242531056

12、4Ks122242oCrOAgsp,101.10.104CrOAg42sK16Lmol101.7s解得：解得：(2) 酸度的影響酸度的影響3910792 .oFe(OH) sp,3K已已知知：解：解：ospKJ Fe3+(aq) + 3OH- -(aq) Fe(OH)3(s)979333oFe(OH)sp,10. 2OHFe3K13oFe(OH)sp,Lmol.FeOH31333931003310010792K13oFe(OH)sp,Lmol.FeOH31235393105361010792K979333oFe(OH)sp,10. 2OHFe3K仍然有：仍然有：(3) 鹽效應(yīng)鹽效應(yīng)(1) 生成

13、水生成水Fe(OH)3(s) + 3H+ (aq) Fe3+ (aq) + 3H2O Fe(OH)3(s) Fe3+ (aq) + 3OH- - (aq) 3H+ (aq) + 3OH- - (aq) 3H2OoFe(OH)sp,3K3owKFe(OH)3(s) + 3H+ (aq) Fe3+ (aq) + 3H2O 331439310792100110792.).(.)(owoFe(OH)sp,o3KKKM(OH)n(s) + nH+ (aq) Mn+ (aq) + nH2O nowospo)(KKK (2) 生成弱酸生成弱酸910322 .oOCaC sp,42K已已知知：解：解：CaC2

14、O4(s) + 2H+ (aq) Ca2+ (aq) + H2C2O4 續(xù)解：續(xù)解：CaC2O4(s) Ca2+ (aq) + C2O42- - oOCaCsp,42KH+(aq) + C2O42- -(aq) HC2O4 - - (aq) H+(aq) + HC2O4- -(aq) H2C2O4 1)(oOCaCa2,42K1)(oOCaCa1,42KCaC2O4(s) + 2H+ (aq) Ca2+ (aq) + H2C2O4 4529210058103751037510322010010.HOCHCaoa2oa1oOCaCsp,24222o42KKKxK另解：另解：45291005810

15、3751037510322.OCHOCOCHCaHOCHCaoa2oa1oOCaCsp,-2422-242422224222o42KKKKCaC2O4(s) + 2H+ (aq) Ca2+ (aq) + H2C2O4 4210058010010.x252210011052.oSnS sp,oZnS sp,KK，已已知知：ZnS(s) + 2H+(aq) Zn2+(aq) + H2S解：解：01901026110071105213722.SHSSHZnHSHZnoSHa2,oSHa1,oZnSsp,-22-222222o22KKKK252210011052.oSnS sp,oZnS sp,KK，已已知知：SnS(s) + 2H+(aq) Sn2+(aq) + H2S續(xù)解：續(xù)解：613725104710261100711001.SHSSHSnHSHSnoSHa2,oSHa1,oSnSsp,-22-222222o22KKKK(3) 生成弱堿生成弱堿131091 .oMn(OH) sp,2K已知：已知：解：解：Mn(OH)2(s) + 2NH4+(aq) Mn2+(aq) + 2NH3H2O4251322210276107411091.).(.)(OHNHOHOHNHMnNHOHNHMnoNHb,oMn(OH)sp,242232242232o32KKKCaSO4(s) + CO32-