Exam (elaborations) Experiment- Molar Solubility, Common-ion Effect (CHM111)

lOMoARcPSD|5967629




Reddy 1
lOMoARcPSD|5967629




Seminar Assignments, Experiment- Molar
Solubility, Common-ion Effect
General Chemistry II/Lab (Nova Southeastern
University)


Experiment 22: Molar Solubility, Common-Ion

Effect Niyanthesh Reddy

Lab Partners: Samir Nacer,

Kristen Date: 03/31/2016

Professor: Dr. Ballester

Lab Assistant: Dr. Sarah Rodriguez

, lOMoARcPSD|5967629




Reddy 2

Abstract

The purpose of this experiment was to understand the molar solubility and solubility constant

of Calcium Hydroxide, Ca(OH)2. Many principles were involved such as, Molar solubility is the

number of moles of salt that dissolves per liter of (aqueous solution), Solubility Product is the

equilibrium constant for a slightly soluble salt at Dynamic Equilibrium, and Common-Ion Effect

is the effect of an ion on the position of the equilibrium (Beran, 2013). In this experiment, a

Titration procedure was conducted, where 0.05 M concentrations of HCl was added to the

basic solution of Calcium Hydroxide to reach the stoichiometric point (indicated by methyl-

orange indicator). The molar solubility of Ca (OH) 2 in solution was 1.5 x 10-2 mol/L and the

average solubility product (Ksp) was 1.3 x 10-5 for Ca (OH) 2. Definitely the hypothesis of this study

was accepted, as first, Calcium Hydroxide being less soluble substance and HCl as being a

strongly titrating solution, so the solubility product would become less saturated, and as the

Common- Ion Effect did occur, so the molar solubility decreased and the equilibrium shifted

to the left (reactants).