14£®Ïà¶ÔÃܶÈΪ1.01µÄº¬3.00%µÄH2O2ÈÜÒº2.50mL£¬Óûc1/5KmnO4=0.200mol/LµÄKMnO4ÈÜÒºÍêÈ«×÷Óã¬Ðè´ËŨ¶ÈµÄKMnO4ÈÜÒº¶àÉÙmL£¿ ½â£º
c1/5KMnO4?0.200mol/LÔò£ºcKMnO4?0.0400mol/LVKMnO4?25?1.01?3.00%?2.5034.02?0.0400?0.0223(L)?22.3(mL)
µÚËÄÕ ϰÌâ
ϰÌâ4-1
4.1 ÏÂÁи÷ÖÖÈõËáµÄpKaÒÑÔÚÀ¨ºÅÄÚ×¢Ã÷£¬ÇóËüÃǵĹ²éî¼îµÄpKb£» (1)HCN(9.21)£»(2)HCOOH(3.74)£»(3)±½·Ó(9.95)£»(4)±½¼×Ëá(4.21)¡£ ½â£º (1) HCN pKb=14-9.25=4.79 (2) HCOOH pKb=14-3.74=10.26 (3) ±½·Ó pKb=14-9.95=4.05 (4) ±½¼×Ëá pKb=14-4.21=9.79
4.2. ÒÑÖªH3PO4µÄpKa=2.12£¬pKa=7.20£¬pKa=12.36¡£ÇóÆä¹²éî¼îPO43-µÄpKb1£¬HPO42-µÄpKb2£®ºÍH2PO4- µÄp Kb3¡£
½â£º PO43- pKb=14-12.36=1.64 HPO42- pKb=2£®14-7.20=6.80
- H2PO4 pKb=14-2.12=11.88
4.3 ÒÑÖªçúçêËá(CH2COOH)2(ÒÔH2A±íʾ)µÄpKal=4.19£¬pKb1=5.57¡£ÊÔ¼ÆËãÔÚpH4.88ºÍ5£®0ʱH2A¡¢
HA-ºÍA2-µÄ·Ö²¼ÏµÊý¦Ä2¡¢¦Ä1ºÍ¦Ä0¡£Èô¸ÃËáµÄ×ÜŨ¶ÈΪ0.01mol¡¤L-1£¬ÇópH£½4.88ʱµÄÈýÖÖÐÎʽµÄƽºâŨ¶È¡£
½â£º pH=4.88 ¡²H+¡³=1.32¡Á10-5 (1.32?10
=0.145
??(H2A)?(1.32?10?5?5)2)?6.46?102?5?1.32?10?5?5?2.69?10?5?6?6.46?10?5
(1.32?10 =0.710 (1.32?10
=0.145 pH=5
?1(HA)??1.32?10?5?6.46?10?5)?6.46?102?5?1.32?10?5?2.69?10?6?6?6?6.46?10?5
?0(A2?)?6.46?10?5?2.96?10?5)?6.46?102?5?1.32?10?2.69?10?6.46?10?5
??(H2A)?(1.0?10?5?5)2(1.0?10=0.109
?5)?6.46?102?5?1.0?10?5?5?2.69?10?5?6?6?6.46?10?5
(1.0?10 =0.702
?1(HA)??1.0?10)?6.46?102?5?6.46?10?5?1.0?10?5?2.69?10?6?6.46?10?5
(1.0?10)?6.46?10?1.0?10?2.69?10?6.46?10
=0.189
pH=4.88 c(H2A)=0.01mol¡¤L-1 c(H2A)=0.145¡Á0.01=1.45¡Á10-3mol¡¤L
--3
c(HA)=0.710¡Á0.01=7.10¡Á10mol¡¤L
--3
c(A2)=0.145¡Á0.01=1.45¡Á10mol¡¤L-1
4.4 ·Ö±ð¼ÆËãH2CO3(pKa1=6.38£¬pKa2=10.25)ÔÚpH=7.10£¬8.32¼°9.50ʱ£¬H2CO3£¬HCO3-ºÍCO32-µÄ·Ö²¼ÏµÊý¦Ä2` ¦Ä1ºÍ¦Ä0¡£ ½â£ºpH=7.10
?0(A2?)?6.46?10?52?5?2.96?10?5?6?5
?2(H2CO3)?(10?7.10?7.10)2(10=0.16
)?102?6.38?10?7.10?7.10?10?6.38?10.25?10?6.38
(10 =0.84
?1(HCO?3)?10?7.10?10)?102?6.38?10?7.10?10?6.38?10?10.25
(10)?10-4
=5.94¡Á10pH=8.32 (10 =0.0112
?0(CO2?3)?10?7.102?6.38?10?10.25?6.38?10?7.10?10?6.38?10?10.25
?2(H2CO3)?(10?8.32?8.32)2)?102?6.38?10?8.32?10?10.25?10?6.38
?1(HCO?3)?10(10?8.32?8.32?10?6.38)?102?6.38?10?8.32?10?6.38?10?10.25 =0.979 (10 =0.0115
pH=9.50
?0(CO2?3)?10?8.32?6.38?10?10.25)?102?6.38?10?8.32?10?6.38?10?10.25
(10 =6.34¡Á10-4
?2(H2CO3)?(10?9.50?9.50)2)?10102?6.38?10?9.50?10?10.25?10?6.38
?9.50(10)?10 =0.851
?1(HCO?3)??10?6.38?9.502?6.38?10?9.50?10?6.38?10?10.25
(10)?10?10?10?10
=0.150
4.5 ÒÑÖªHOAcµÄpKa =4.74£¬NH3¡¤H20µÄpKb=4.74¡£¼ÆËãÏÂÁи÷ÈÜÒºµÄpH£º
-1
(1)0.10 mol¡¤LHOAc£» (2)0.10 mol¡¤L-1NH3¡¤H2O£»
-1-1
(3)0.15 mo1¡¤LNH4Cl£» (4)0.15 mol¡¤LNaOAc¡£
-1
½â£º(1) 0.1mol¡¤LHAc
c?0(CO2?3)?10?9.502?6.38?10?10.25?6.38?10.25?6.38?9.50 ¡ß
Ka?0.110?10?5?4.74c?Ka?0.1?10?3?4.74?10Kw
?1.35?10¡à¡²H+¡³=0.1?10 pH=2.87
-1
(2) 0.10 mol¡¤LNH3¡¤H2O
?cKb?mol?L
?1?0.110?4.74?105?4.74c?Kb?0.1?10?1.35?10?3?4.74?10Kw?OH???-1
0.1?10mol?L?1pH?11.13(3) 0.15 mo1¡¤LNH4Cl
0.15?c??105Ka10?9.26c?Ka?0.15?10?H?9.26
?10Kw?9.03?10?6????0.15?10?9.26mol?L?1.04 pH?5-1
(4) 0.15 mol¡¤LNaOAc
?cKb??0.1510?9.26?105?9.26c?Kb?0.15?10?9.03?10?6?9.26?10Kw?OH???0.15?10mol?L?1pH?8.96
4.6¼ÆËãŨ¶ÈΪ0.12 mol¡¤L-1µÄÏÂÁÐÎïÖÊË®ÈÜÒºµÄpH(À¨ºÅÄÚΪpKa)¡£(1)±½·Ó(9.95)£»(2)±ûÏ©Ëá(4.25)£»(3)ßÁवÄÏõËáÑÎ(C5H5NHN03)(5.23)¡£ ½â£º(1) ±½·Ó(9.95)
?c?Ka?0.12?10?H?9.95
?10Kw?3.67?10?6cKa??10.1210?9.95?105????0.12?10?9.95mol?LpH?5.44(2) ±ûÏ©Ëá(4.25)
?c?Ka?0.12?10?H?4.25
?10Kw?2.60?10?3cKa??10.1210?4.25?105????0.12?10?4.25mol?LpH?2.58
(3) ßÁवÄÏõËáÑÎ(C5H5NHNO3)(5.23)
?c?Ka?0.12?10?H?5.23
?10Kw?8.4?10-1
?4cKa?1?0.1210?5.23?105????0.12?10?5.23mol?L
4.7 ¼ÆËãŨ¶ÈΪ0.12 mol¡¤LµÄÏÂÁÐÎïÖÊË®ÈÜÒºµÄpH(pK£º¼ûÉÏÌâ)¡£ (1)±½·ÓÄÆ£»(2)±ûÏ©ËáÄÆ£»(3)ßÁड£ ½â£º(1) ±½·ÓÄÆ
Kb?10?4.05pH?3.08?c?Kb?0.12?10?OH?4.05?10Kw?3.27?10?3cKb?0.1210?1?4.05?105????0.12?10?4.05mol?LpH?11.52
(2) ±ûÏ©ËáÄÆ