Answer:
the concentration of free Ca2⁺ in this solution is 7.559 × 10⁻⁷
Explanation:
Given the data in the question;
+
⇄ ![CaY^{2-](https://tex.z-dn.net/?f=CaY%5E%7B2-)
Formation constant Kf
Kf =
/ ( [
][
] ) = 5.0 × 10¹⁰
Now,
[
] =
; ∝₄ = 0.35
so the equilibrium is;
+
⇄
+ 4H⁺
Given that;
=
{ 1 mol
reacts with 1 mol
}
so at equilibrium,
=
= x
∴
+
⇄ ![CaY^{2-](https://tex.z-dn.net/?f=CaY%5E%7B2-)
x + x 0.010-x
since Kf is high, them x will be small so, 0.010-x is approximately 0.010
so;
Kf =
/ ( [
][
] ) =
/ ( [
][
] ) = 5.0 × 10¹⁰
⇒
/ ( [
][
] ) = 5.0 × 10¹⁰
⇒ 0.010 / ( [x][ 0.35 × x] ) = 5.0 × 10¹⁰
⇒ 0.010 / 0.35x² = 5.0 × 10¹⁰
⇒ x² = 0.010 / ( 0.35 × 5.0 × 10¹⁰ )
⇒ x² = 0.010 / 1.75 × 10¹⁰
⇒ x² = 0.010 / 1.75 × 10¹⁰
⇒ x² = 5.7142857 × 10⁻¹³
⇒ x = √(5.7142857 × 10⁻¹³)
⇒ x = 7.559 × 10⁻⁷
Therefore, the concentration of free Ca2⁺ in this solution is 7.559 × 10⁻⁷