第13章 氧化还原滴定法习题答案
以下题目注意有效数字取舍！
4．
-+2+解： 2MnO +8HO+542H2O+6H=2Mn2+52O5--?n(H2O2)=?c(MnO)V(MnO44)? ?25－－?3??c(MnO)V(MnO)?10M(HO442)2?2??250.025.00 H2O2(g/100mＬ)??100 25.005－3?0.025?322?7.68?10?34.02250.0 ?2?100
25.00?25.00= 2.384
5．
2++2+3+解： MnO－4+5Fe+8H=Mn+5Fe+4H2O
－－n(Fe2+)=5n(MnO－4)=5c(MnO4)V(MnO4)
15 n(Fe2O3)=n(Fe)?c(MnO－4)V(MnO－)4 (Fe2O3~2Fe)
2255 m(Fe2O3)=c(MnO－4)V(MnO－)4M(FeO2)=3?0.01000?8.00?10－3?159.7
22 ?0.0319 gm(Al2O3)?0.1100?0.0319?0.0781
w(Fe2O3)?0.0319?0.0319 1.0000.0781w(Al2O3)??0.0781
1.0006．
2－+3+解： Cr +－6I+14H=2C2r+32O72I+7HO2－2－ Cr2O7~3I2~6S2O3?m12-2-?n(KI)?6n(K2Cr2O7)?6??c(S2O3)V(S2O3)??M6? 1
?0.1941?6???0.1000?10.00?10?3??166.0n(KI)?M(KI)294.186? w(KI)???m0.5186(6.595?10?4?1.667?10?4)?166.0 ?0.5186(6.595?10?4?1.667?10?4)?166.0?=0.948
0.5187．
解：(1) H2SO4+2NaOH= Na2SO4+2 H2O
n(H2SO4)?1n(NaOH) 21?0.1000?40.00?10?3?98.07n(H2SO4)?M(H2SO4)m(H2SO4)??1000?2?100050.0050.00 = 3.923g
(2) MnO4-+5Fe2++8H+=Mn2++5Fe2++4H2O
1n(MnO-4)?n(Fe2+)
51?0.1000?25.00?10?3?158.03m(KMnO4)?5?1000?1.580
50.0010．
解： MnO2?H2C2O4?2H??Mn2??2CO2??2H2O
? 5HCO?2Mn?O224余()4?6?H2?2M?n10?C?O 28HO2 n(MnO)n2?(On()H?n(H2C2O4)余 2H2C4?2C2O4总)?m(H2C2O4)5? ???c?MnO-4?V?MnO-4??
?M(H2C2O4)2??0.75005?3???0.02000?30.00?10??86.94n(MnO2)?M(MnO2)?126.072?? w(MnO2)? ?m0.5000 ?
?0.005949?0.0015??86.940.5000?0.773 6 2