仪器分析课后习题答案1概要 下载本文

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? +?左=?Zn2?,Zn0.0592Zn2??lg???

20.0592 lg0.1 =-0.764+

2=-0.793V

右:

Ag??e?Ag???0.0592lg?Ag??

?右???Ag?,Ag?0.799?0.0592lg0.01

=0.681V

E??右??左

?0.681???0.793?

=1.474V

8.解:

E?0,所以是原电池。

左边:

2HA?2e?H2?2A?

??

?左??H,H?0.0592lg??H???2????左??H?0.0592lgH???,H?2

=0.0592lg??H???

E??右??左

?0.413?0.244?0.0592lg?H???

?0.0592lg??H????0.169 ??3??H?1.4?10mol/l ??

HA?H??A?

?? ????HA????K??HA?1.4?10?3?0.116 =

0.215 =7.6?10

?4

9.解:E??右??左

0.921?0.2443??左

?左??0.6767V

左边:CdX2?4?2e?Cd?4X?

??左??Cd2?,Cd?0.05922lg??Cd2??? Cd2??4X?CdX2?4 K??CdX2?4??稳? ??Cd2?????X??4? ?Cd?2??2?????CdX4??

K??4稳??X?

??左?2?,Cd?0.0592??CdX2??4?Cd2lg?

KX??4稳????0.6767??0.403?0.05920.22lgK4稳?0.150?K稳?7.0?1011

10-.解: E??右??左

?左??0.648V7

??左??Cd2?,Cd?0.05922lg??Cd2??? Cd?2X??CdX2

K2?2sp???Cd????X???

?K?Cd2????sp??X??2

?0.893?0.2443??左

??左??Cd2?,Cd?Ksp0.0592lg?22?X???

?0.6487??0.403?Ksp0.0592lg22?0.02?

Ksp?2.0?10?12

第十二章 电位分析法

10.(1)E=E右-E左

=E

θ

+RT/ZFln[Fe3+]/[Fe2+]-ESCE

=(0.771+0.059lg0.025/0.015)-0.2443 =0.784-0.2443 =0.540 (2)E=E右-E左

=E

θ

+RT/ZFln[Zn2+]-ESCE

=(-0.764+0.059/2lg0.00228)-0.2443 =-0.842-0.2443 =-1.085 (3)I3-+2e=3I- E=E右-E左

=E

θ

+RT/ZFln[I3+]/[I+]-EAg/AgCl

=(0.545+0.059/2lg0.00667/0.004333)-0.194 =0.690-0.194 =0.496 12.解:E=E右-E左

=EθAg2CrO4/Ag-0.059/2lgCrO42--ESCE

θ

=EAg2CrO4/Ag+0.059/2P(CrO4)-ESCE

代入数字得:0.386=0.446+0.059/2P(CrO4)-0.2443 解得:P(CrO4)=6.25 13.解:E

?EpH?EAg/AgCl

?K-0.0592pH

?Es?K-0.0592pHsEx?K-0.0592pHxEs?Ex

0.0592

pHx?pHs?

?4.006??0.2094???0.2806?

0.0592 =5.21 14.解:E?ECu2??ESCE

?K??K,?0.0592lgaCu2??ESCE 2

0.0592pMg 2

2?Es?Ex?pMx?pMs?

0.0592??lg?3.25?10?3???3.772??0.124?0.086? 0.0592

17.解:依题意有:

(1)当aNa+=0.1000mol/L时,E1=67mv=0.067V 当aK+=0.1000mol/L时,E2=113mv=0.113V

E=K+0.059lg(ak++Kk+,Na+·an/aNa+) 又因为:n=1,a=1

所以:E1=K+0.059lg(Kk+,Na+·aNa+)=0.067V E2=K+0.059lg(ak+)=0.113V

得:ΔE=E1-E2=0.059lg(Kk+,Na+·aNa+)/ak=0.067-0.113=-0.046V 解得:Kk+,Na+=0.166

(2)误差=KK?,Na??aNa?aK???11?100%

=16.6%

第十三章电解与库伦分析法

7解:?Ag???????0.0592lgAg?????Ag Ag,Ag?0.799?0.0592lg0.01?0

=0.681V

??Cu??Cu

0.05922??lg?Cu??Ag

??20.0592?0.337?lg2

22??,Cu =0.346V

??Ag??Cu?Ag先析出,?Ag???Ag

(2)Ag析出完全时电位为:

?,Ag??5??0.0592lg?Ag?10??Ag ????

?0.799?0.0592lg?0.01?10?5??0

=0.385V ??Ag ??Ag ?Ag8.解: ?Cu,,??Cu

??Cu

?和Cu2?可完全分离。阴极控制电位在0.385V或0.385-0.346V之间

???Cu?2?,Cu

0.05922??lg?Cu??Cu

??20.0592?0.337?lg0.1?0

20.0592lg0.1??Sn 20.0592??0.136?lg0.1?0

2 =0.307V

? ?Sn??Sn?2?,Sn

=-0.166V ??Cu??Sn

?阴极上Cu先析出

Cu析出完全时,阴极电位为:

0.0592,?lg0.1?10?5??Cu ?Cu??Cu2?,Cu?20.0592 =0.337-6?+0

2

?? =0.159V

,?Cu??Sn ?Cu和Sn可完全分离

?阴极电位控制在0.159V或-0.166?0.159V之间,即可完全分离Cu和Sn。

9.解:it?it?10?kt