Question

The concentration of a saturated solution of an ionic compound at 25 oC is 7.00E-4. The formula for this compound is XQ3. What is the concentration of Q at equilibrium? Answer Submitted: Your final submission will be graded when the time limit is reached. Tries 1/98 Previous Tries What is the Ksp value for XQ3?

Answer 1

Answer:

Conc of Q at Equilibrium 2.1 × 10⁻³ mol/dm³

Ksp = 1.57 × 10⁻¹² mol/dm³

Explanation:

The Solubility of the Ionic compound is given by s

where s = 7 × 10⁻⁴ mol/dm³

solubility equation is given as follows

                     XQ₃(s)           ⇄           X³⁺(aq)          +          3Q⁻(aq)

                         s                                s                               3s

let the concentration of each be s

The concentration of Q = 3s

⇒                                [Q] = 3 × 7 × 10⁻⁴ mol/dm³

⇒                                [Q] = 2.1 × 10⁻³ mol/dm³

hence,

                                   Ksp =      [X³⁺][Q⁻]³

                                   Ksp =      [s][3s]³

                                   Ksp =      [7 × 10⁻⁴ ][2.1 × 10⁻³]³

                                   Ksp =      1.57 × 10⁻¹² mol/dm³