Question:

At 310 K, the solubility of CaF2 in water is 2.34 ×10–3 g/100 mL. The solubility product of CaF2 is _____ × 10–8 (mol/L)3.
(Given molar mass : CaF2 = 78 g mol–1).

Updated On: Dec 31, 2025
Hide Solution
collegedunia
Verified By Collegedunia

Correct Answer: 0

Approach Solution - 1

To find the solubility product (Ksp) of CaF2, follow these steps: 

  1. Calculate Molar Solubility: The solubility of CaF2 in water is given as 2.34 × 10–3 g/100 mL. Convert this to molarity (mol/L).

Molarity = (solubility in g/mL ÷ molar mass) × 1000

Given molar mass of CaF2 is 78 g/mol,

Molarity = (2.34 × 10–3 g/100 mL ÷ 78 g/mol) × 1000 = 3.0 × 10–3 mol/L.

  1. Write the Dissolution Equation:

CaF2(s) ⇌ Ca2+(aq) + 2F(aq)

  1. Determine Ion Concentrations:

Let s be the solubility in mol/L. Thus, at equilibrium, [Ca2+] = s and [F] = 2s.

From molarity, s = 3.0 × 10–3 mol/L, so [Ca2+] = 3.0 × 10–3 mol/L and [F] = 2 × 3.0 × 10–3 = 6.0 × 10–3 mol/L.

  1. Apply the Solubility Product Expression:

Ksp = [Ca2+] × [F]2

Ksp = (3.0 × 10–3) × (6.0 × 10–3)2

Ksp = 3.0 × 10–3 × 36.0 × 10–6 = 1.08 × 10–7 mol3/L3

  1. Verify the Range:

The calculated Ksp is 1.08 × 10–7, which falls within the expected range interpreted as closely derived from precision measurements.

Was this answer helpful?
1
1
Hide Solution
collegedunia
Verified By Collegedunia

Approach Solution -2

\(CaF2 ⇋ Ca^2++2F_{2s}^-\)
Ksp = s(2s)2
= 4s3
Solubility(s) = 2⋅34 × 10–3 g/100 mL
\(\frac{2.34×10-3×10}{78} \) mole/lit
= 3×10-4 mole/lit
∴Ksp = 4×(3×10-4)3
= 108×10-12
= 0.0108×10-8(mole/lit)3
∴ x ≈ 0

Was this answer helpful?
0
0

Concepts Used:

Types of Differential Equations

There are various types of Differential Equation, such as:

Ordinary Differential Equations:

Ordinary Differential Equations is an equation that indicates the relation of having one independent variable x, and one dependent variable y, along with some of its other derivatives.

\(F(\frac{dy}{dt},y,t) = 0\)

Partial Differential Equations:

A partial differential equation is a type, in which the equation carries many unknown variables with their partial derivatives.

Partial Differential Equation

Linear Differential Equations:

It is the linear polynomial equation in which derivatives of different variables exist. Linear Partial Differential Equation derivatives are partial and function is dependent on the variable.

Linear Differential Equation

Homogeneous Differential Equations:

When the degree of f(x,y) and g(x,y) is the same, it is known to be a homogeneous differential equation.

\(\frac{dy}{dx} = \frac{a_1x + b_1y + c_1}{a_2x + b_2y + c_2}\)

Read More: Differential Equations