Q.

The solubilities of AgCl in water, 0.01M CaCl2, 0.01M NaCl and 0.05M AgNO3 are denoted by S1,S2,S3 and S4 respectively. Which of the following relationships is correct

1 S1>S2>S3>S4  
2 S1>S3>S2>S4  
3 S1>S2=S3>S4  
4 S1>S3>S4>S2  

Ans.

(2)

Solubility of AgCl in water:    AgClAg++Cl-

Ksp=[Ag+][Cl-]=(S1)(S1)=S12

  S1=Ksp=1.34×10-5 mole/litre

Solubility of AgCl in 0.01M CaCl2

[Ag+]=S2,    [Cl-]=(2×0.01+S2)         Ksp=[Ag+][Cl-]          S2=9×10-9mole/litre

Solubility of AgCl in 0.01M NaCl

[Ag+]=S3,    [Cl-]=(0.01+S3)        1.8×10-10=S3(0.01+S3)     S3=1.8×10-8mole/litre

Solubility of AgCl in 0.05M AgNO3

[Ag+]=(0.05+S4),    [Cl-]=S4      S4=3.6×10-9mole/litre

From the values of solubility we get    S1>S3>S2>S4