Question

The solubility of Mg(OH)2 is 3.72 x10-SM. The solubility product Ksp is a. 1.38 x10-9 b. 2.06 x 10-13 C. 5.14 x10-14 d. 2.68 x10-10 e. 3.07 x x10-5

Answer 1

(1) Write the ionisati on Mg (OH), as follows: Mg(OH), (s) > Mg2* + 2OH 3.72x10- M Given solubility of Mg OH).s = The solubility of Mg2* and OH is as follows Mg (OH), (s) > Mg 20H 2s S Calculate the solubility product as follows: Kg= (2s) = 4s3 K4(3.72x 109) 206 x10-15 Kp 2.06x10-13 Therefore, the correct option is |b (2) Initi al concentrati on of KOH, M 3.75 M Initi al volume of KOH, ? = Final concentrati on of KOH, M =0.180 M Final volume of KOH, V 250.0 mL Since moles of KOH do not change initi al moles final moles M MV Му, M1 0.180 Mx250.0 mL 3.75 M 12 mL 10 mL (closest value) Therefore, the correct option is b