   Chapter 16, Problem 37E

Chapter
Section
Textbook Problem

# Calculate the solubility (in moles per liter) of Fe(OH)3 (Ksp = 4 × 10−38) in each of the following.a. waterb. a solution buffered at pH = 5.0c. a solution buffered at pH = 11.0

(a)

Interpretation Introduction

Interpretation: The solubility product of Fe(OH)3 is given. The solubility (in mol/L ) of Fe(OH)3 is to be calculated for each given conditions.

Concept introduction: Solubility is defined as the maximum amount of solute that can dissolve at a certain amount of solvent at certain temperature. The solubility product, Ksp is the equilibrium constant that is applied when salt partially dissolve in a solvent. The solubility product of dissociation of AxBy is calculated as,

Ksp=[A]x[B]y

The ion product of water is calculated using the formula,

Kw=[H+][OH]

Explanation

Explanation

To determine: The solubility of Fe(OH)3 in water.

The solubility of Fe(OH)3 in water is 4×1017mol/L_ .

Given

Solubility product of Fe(OH)3 is 4×1038 .

Since, solid Fe(OH)3 is placed in contact with water. Therefore, compound present before the reaction is Fe(OH)3 and H2O . The dissociation reaction of Fe(OH)3 is,

Fe(OH)3(s)Fe3+(aq)+3OH(aq)

Since, Fe3+ does not dissolved initially, hence,

[Fe3+]initial=0

The solubility of Fe(OH)3 can be calculated from the concentration of ions at equilibrium.

It is assumed that smol/L of solid is dissolved to reach the equilibrium. The meaning of 1:3 stoichiometry of salt is,

smol/LFe(OH)3smol/LFe3++3smol/LOH

Since, in a neutral solution, the initial concentration of OH is 1×107 . Hence, in a saturated solution, the concentration of OH is 1×107+3s . But the value of s is expected to be very small, therefore, the concentration of OH is approximated to,

1×107+3s1×107

Make the ICE table for the dissociation reaction of Fe(OH)3

(b)

Interpretation Introduction

Interpretation: The solubility product of Fe(OH)3 is given. The solubility (in mol/L ) of Fe(OH)3 is to be calculated for each given conditions.

Concept introduction: Solubility is defined as the maximum amount of solute that can dissolve at a certain amount of solvent at certain temperature. The solubility product, Ksp is the equilibrium constant that is applied when salt partially dissolve in a solvent. The solubility product of dissociation of AxBy is calculated as,

Ksp=[A]x[B]y

The ion product of water is calculated using the formula,

Kw=[H+][OH]

(c)

Interpretation Introduction

Interpretation: The solubility product of Fe(OH)3 is given. The solubility (in mol/L ) of Fe(OH)3 is to be calculated for each given conditions.

Concept introduction: Solubility is defined as the maximum amount of solute that can dissolve at a certain amount of solvent at certain temperature. The solubility product, Ksp is the equilibrium constant that is applied when salt partially dissolve in a solvent. The solubility product of dissociation of AxBy is calculated as,

Ksp=[A]x[B]y

The ion product of water is calculated using the formula,

Kw=[H+][OH]

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started 