Let the solubilities of `AgCI` in `H_(2)O`, and in `0.01M CaCI_(2), 0.01M NaCI`, and `0.05M AgNO_(3)` be `S_(1),S_(2),S_(3),S_(4)`, respectively. What is the correct relationship between these quantites.

Options

A. `S_(1) gt S_(2) gt S_(3) gt S_(4)`
B. `S_(1) gt S_(2) = S_(3) gt S_(4)`
C. `S_(1) gt S_(3) gt S_(2) gtS_(4)`
D. `S_(4) gt S_(2) gt S_(3) gt S_(1)`

Answer

C

Explanation

i. `AgCI + H_(2)O rArr Ag^(o+) (aq) +CI^(Theta) (aq) ..S_(1)`
ii. `AgCI` in `0.01M CaCI_(2), …S_(2)` Concentration of `CI^(Theta) = 2xx 0.01 = 0.002M`
iii. `AgCI in 0.01M NaCI, ….S_(3)` Concentration of `CI^(Theta) = 0.01M`
iv. `AgCI is 0.05M. AgNO_(3), ....S_(4)` Concentration of `Ag^(o+) = 0.05`.
Since both `CI^(Theta)` ions and `Ag^(o+)` ions acts as common ion. So larger the concentration of `Ag^(o+)` or `CI^(Theta)` ions, more is the supression of ionisation of `AgCI` and hence less will be solubility of `AgCI`.
`:.` Solubility order
`S_(1) gt S_(3) gt S_(2) gt S_(4)`