To a solution containing [ Cl − ] = [ AsO 4 3 − ] = 0.01 M , AgNO 3 is added slowly. Then which of the following is correct statement : [Given : K sp ( AgCl ) = 1 0 − 10 , K sp ( Ag 3 AsO 4

Question

To a solution containing [ Cl − ] = [ AsO 4 ​ 3 − ] = 0.01 M , AgNO 3 ​ is added slowly. Then which of the following is correct statement : [Given : K sp ​ ( AgCl ) = 1 0 − 10 , K sp ​ ( Ag 3 ​ AsO 4 ​ ) = 1 0 − 23 ]

TestHub · Accepted Answer

To determine which compound precipitates first, we compare the concentration of Ag $^{+}$ required for precipitation for each salt.

For AgCl:

$K_{s p} (A g Cl) = [A g^{+}] [C l^{-}]$

$1 0^{- 10} = [A g^{+}] (0.01)$

$[A g^{+}] = \frac{1 0 ^{- 10}}{0.01} = 1 0^{- 8} M$

For Ag₃AsO₄:

$K_{s p} (A g_{3} A s O_{4}) = [A g^{+}]^{3} [A s O_{4}^{3 -}]$

$1 0^{- 23} = [A g^{+}]^{3} (0.01)$

$[A g^{+}]^{3} = \frac{1 0 ^{- 23}}{0.01} = 1 0^{- 21}$

$[A g^{+}] = (1 0^{- 21})^{1/3} = 1 0^{- 7} M$

Since AgCl requires a lower $[A g^{+}]$ ( $1 0^{- 8}$ M) to precipitate compared to Ag₃AsO₄ ( $1 0^{- 7}$ M), AgCl will precipitate first.

The final answer is $B$ .

Chemistry - Ionic Equilibrium Question with Solution | TestHub

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