7. Strontium hydroxide dissolves in water according to the following equation. The Ksp expression fo — Solubility Equilibria, Common Ion Effect, Particulate Diagrams Chemistry Question
Problem Context
7. Strontium hydroxide dissolves in water according to the following equation. The Ksp expression for strontium hydroxide is provided.
Sr(OH)2(s) ⇌ Sr2+(aq) + 2 OH−(aq) Ksp = [Sr2+][OH−]2
(a) A student draws the particulate diagram shown to represent the ions present in an aqueous solution of Sr(OH)2. (Water molecules are intentionally omitted.) Identify the error in the student’s drawing.
(b) The student prepares a saturated solution by adding excess Sr(OH)2(s) to distilled water and stirring until no more solid dissolves. The student then determines that [Sr2+] = 0.043 M in the solution.
(i) Calculate the value of [OH−] in the solution.
(ii) Calculate the value of Ksp for Sr(OH)2.
(c) The student prepares a second saturated solution of Sr(OH)2 in aqueous 0.10 M Sr(NO3)2 instead of water. Will the value of [OH−] in the second solution be greater than, less than, or equal to the value in the first solution? Justify your answer. (Assume constant temperature.)