TOLC 2020 q. 51

Practice Question Solving
1

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  1. Under suitable conditions, the solubility product of Zn(OH)2 is 1.2x10-17. Which of the following statements is correct?
    A. The solubility product of Zn(OH)2 does not depend on the temperature
    B. The solubility of Zn(OH)2 does not change if NaOH is added in solution C. The solubility product of Zn(OH)2 does not depend on pH
    D. The solubility product of Zn(OH)2 varies if ZnCl2 is added in solution
    E. The solubility of Zn(OH)2 does not change if ZnCl2 is added to the solution
    notlom er

can someone explain why D is right,
and how does the solubility changes if NaOH is added (B), but also does not depend on pH (C)?

2

In the solution of Zn(OH)2 there exists an equilibrium between Zn(OH)2 and Zn2+ and OH-. Just try to apply le chaterlier principle to this equilibrium, and you will understand the answer easily.