电解质溶液习题课

1. 在一定温度下稀释电解质溶液，电导率κ和摩尔电导率Λm将怎么变化？

A. κ增大，Λm减小 B. κ增大，Λm增大 C. κ减小，Λm 增大 D. κ先增后减，Λm增大 E. κ变化不一定，Λm增大

2. 用同一电导池分别测定质量摩尔浓度为m1=0.01mol?kg-1和m2=0.10mol?kg-1的两种电解

质溶液，其电阻R1=1000Ω，R2=500Ω，则它们的摩尔电导率之比Λm,1:Λm,2为（ ） A. 1:5 B. 5:1 C. 10:5 D. 5:10

3. 极限稀释条件下，CaCl2的摩尔电导率与其离子的摩尔电导率的关系是（ ） A. ?m,CaCl2??m,Ca2???m,Cl? B. ??m,CaCl2????????1? ?m,Ca2????m,Cl?2C. ?m,CaCl2??m,Ca2??2?m,Cl? D. ?m,CaCl2?2?m,Ca2???m,Cl?

4. ?m(BaSO4,298K)?2.870?10S?m?mol，请问?m(BaSO4,298K)的值是多

少？

5. 298K时，已知如下物质的摩尔电导率数据： 物质 Λm / (10-2S?m2?mol-1) LiI 1.17 H+ 3.50 LiCl 1.15 ?22?1????12已知LiCl中的t+=0.34，则HI中的H+的迁移数为（设电解质全部电离） A. 0.82 B. 0.18 C. 0.34 D. 0.66

6. 质量摩尔浓度为1.0mol?kg-1的K4[Fe(CN)6]溶液的离子强度为（ ）

A. 15mol?kg-1 B. 10mol?kg-1 C. 7mol?kg-1 D. 4mol?kg-1

7. 298K时，有质量摩尔浓度均为0.001mol?kg-1的下列电解质溶液，其离子平均活度因子

γ±最大的是（ ）

A. CuSO4 B. CaCl2 C. LaCl3 D. NaCl

8. 质量摩尔浓度为m的FeCl3溶液（设其能完全解离），平均活度因子为γ±，则FeCl3的活

度a为（ ）

?m?4?m?4?m?4?m?A. ???? B. 4????? C. 4????? D. 27?????

?m??m??m??m?4?44

9. Al2(SO4)3的化学势μ与Al3+，SO42-的化学势μ+，μ-之间的关系为（ ） A. μ=μ++μ- B. μ=2μ++3μ- C. μ=3μ++2μ- D. μ=μ+×μ-

10. 强电解质MgCl2水溶液，其离子平均活度a±与电解质活度aB之间的关系为（ ） A. a±=aB B. a±=aB3 C. a±=aB1/2 D. a±=aB1/3

11. AgBr(s)在纯H2O和质量摩尔浓度都是0.1mol?kg-1的下列电解质溶液中： （1）NaNO3 （2）NaI （3）Cu(NO3)2 （4）NaBr （5）H2O 胺AgBr(s)的溶解度有小到大排列的次序为（ ）

A. (1) < (2) < (3) < (4) < (5) B. (4) < (5) < (2) < (1) < (3) C. (5) < (2) < (4) < (1) < (3) D. (4) < (5) < (1) < (3) < (2)

12. 四种浓度均为0.01mol?dm-3，现欲按它们摩尔电导率Λm值由大到小排一个次序。正确的

排序是（ ）

A. NaCl > KCl > KOH > HCl B. HCl > KOH > KCl > NaCl C. HCl > NaCl > KCl > KOH D. HCl > KOH > NaCl > KCl

13. 在一定温度和浓度的水溶液中，一般情况是带相同电荷数的离子的摩尔电导率随离子半

径的增大而减小。原因是（ ）

A. 离子的电迁移率依次减小 B. 离子的水化作用依次减弱 C. 离子的迁移数依次减小 D. 电场强度的作用依次减弱

14. 以m(AgNO3)=0.0100mol?kg-1溶液为电解液，用银作电极，在298K时，测得串联的银

库伦计中沉淀银的质量为mAg=3.210×10-5kg，在2.009×10-2kg的阳极液中含银的质量mAg(+)=3.966×10-5kg，2.712×10-2kg的阴极液中含银的质量mAg(-)=1.114×10-5kg，根据Hittorf法计算Ag+及NO3-的迁移数t+和t-。

15. 298K，1kg的浓度为5.00×10-3mol?kg-1的盐酸溶液： （1）当作为理想溶液处理时，溶液的pH是多少？ （2）当作为非理想溶液处理时，溶液的pH是多少? （3）当溶液中加入2.34×10-4kg的NaCl，溶液总体积不变，溶液的pH又为多少？

16. 在298K时，已知AgCl(s)饱和水溶液的质量摩尔浓度为1.27×10-5mol?kg-1,

AgCl(s)?Ag?(aAg?)?Cl?(aCl?)

（1） 用Debye-Hückel公式计算该饱和溶液的离子平均活度因子γ±和AgCl(s)解离反应的

??Gm。已知常数A=0.509(mol?kg-1)-0.5。

（2）若将AgCl(s)溶在KNO3溶液中，设此时混合溶液的离子强度I=0.010mol?kg-1，计算这时AgCl(s)饱和溶液的质量摩尔浓度。

17. The mobility of a chloride ion in aqueous solution at 25oC is 7.91×10-8m2s-1V-1. Calculate the

molar ionic conductivity.

18. The mobility of a Li+ ion in aqueous solution is 4.01×10-8m2s-1V-1 at 25oC. The potential

difference between two electrodes placed in the solution is 12.0V, if the electrodes are 1.0cm

apart, what is the drift speed of the ion?

19. The limiting molar conductivities of KCl, KNO3 and AgNO3 are 14.99mSm2mol-1,

14.50mSm2mol-1, and 13.34mSm2mol-1, respectively (all at 25oC). What is the limiting molar conductivity of AgCl at this temperature?

20. Conductivities are often measured by comparing the resistance of a cell filled with the sample

to its resistance when filled with some standard solution, such as aqueous potassium chloride. The conductivity of water is 76mSm-1 at 25oC and the conductivity of 0.1moldm-3 KCl(aq) is 1.1639Sm-1. A cell had a resistance of 33.21Ω when filled with 0.100moldm-3 KCl(aq) and 300.0Ω when filled with 0.100 moldm-3 CH3COOH(aq). What is the molar conductivity of acetic acid at that concentration and temperature?

21. The resistance of a series of aqueous NaCl solutions, formed by successive dilution of a sample, were measured in a cell with cell constant (the constant C in the relation κ=C/R) equal to 0.2063cm-1. The following values were found: c/(moldm-3) R/Ω 0.00050 3314 0.0010 1669 0.0050 342.1 0.010 174.1 0.020 89.08 0.050 37.14 Verify that the molar conductivity follows the Kohlrausch law and find the limiting molar conductivity. Determine the coefficient K. Use the value of K (which should depend only on the nature, not the identity of the ions) and the information that λ(Na+)=5.01mSm2mol-1 and λ(I-)=7.68mSm2mol-1 to predict (a) the molar conductivity , (b) the conductivity, (c) the resistance it would show in the cell, of 0.010moldm-3 NaI(aq) at 25oC.

22. After correction for the water conductivity, the conductivity of a saturated aqueous solution of AgCl at 25oC was found to be 0.1887mSm-1. What is the solubility of silver chloride at this temperature?

23. The mobilities of H+ and Cl- at 25oC in water are 3.623×10-7m2s-1V-1 and 7.91×10-8m2s-1V-1, respectively. What proportion of the current is carried by the protons in 10-3M HCl(aq)? What fraction do they carry when the NaCl is added to the acid so that the solution is 1.0moldm-3 in the salt? Note how concentration as well as mobility governs the transport of current.

参考答案： 1. E

注：电导率具有加合性，但是并不是说随着浓度增加可以变为超导体。 2. B 3. C

4. 1.435×10-2S?m2?mol-1 5. A 6. B 7. D 8. D 9. B 10. D 11. D 12. B 13. B

14. t+=0.44, t-=0.56

15. (1)2.301; (2)2.337; (3)2.349

注：用平均活度作为质子的活度，计算pH值。 16. (1) 55.885kJ; (2) 1.422×10-5mol?kg-1 17. 7.63mS?m2?mol-1 18. 4.81×10-5m?s-1 19. ?m?AgCl???m?AgNO3???m?KCl???m?KNO3?

????20. 0.613mS?m2?mol-1 21. 科尔劳琴 ?m vs.

c

0.01280.0124y=0.0126-0.0002421*x?m/ (Sm2mol-1)0.01200.01160.0112012340.5-1.55678c/ (molm)

??2?1??m,NaCl??m,Na???m,Cl??0.01269S?m?mol

采用上述图形中的红色直线公式的系数K，得到NaI的摩尔电导率与浓度的关系式：y=0.01269-0.002421*x。当NaI的浓度为0.010moldm-3，即10molm-3，代入前面的公式得到其摩尔电导率为0.01192 Sm2mol-1，电导率为0.1192Sm-1，电阻为173.0Ω。

22. 1.36×10-2mol?m-3

23. t+=0.82

加入NaCl，采用公式tB?QBIBnzr??BBB QI?nBzBrBBt??1molm?3?1?3.623?10?7m2s?1V?1?0.00281molm?3?1?3.623?10?7m2s?1V?1?1001molm?3?1?7.91?10?8m2s?1V?1?1000molm?3?1?5.19?10?8m2s?1V?1