Chapter 20, Problem 40GQ

(a)

Interpretation Introduction

Interpretation: The $pH$ at which $\left[{\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}\right]\text{=}\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]$ should be determined using the given graph.

Concept introduction:

Ocean acidification: The increase in concentration of carbon-dioxide in the atmosphere leads to ocean acidification. The amount is increasing day by day and this increase will lead to higher concentrations of dissolved ${\text{CO}}_{\text{2}}$ and as a result the amount of carbonic acid also will be higher.

The concentration of hydronium ion is a key factor for many biochemical reactions. So variation may affect the organisms in the oceans.

The relationship between ocean $\text{pH}$ and atmospheric ${\text{CO}}_{\text{2}}$ is that they are inversely proportional. The hydrogen ion concentration will be increased as the concentration of dissolved ${\text{CO}}_{\text{2}}$ increases and thus $\text{pH}$ will be decreased.

Answer to Problem 40GQ

The $\text{pH}$ at which the $\left[{\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}\right]\text{=}\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]$ is approximately 6.4

Explanation of Solution

If the concentration of dissolved ${\text{CO}}_{\text{2}}$ is increased, then the $\text{pH}$ will be decreased as a result of the increase in concentration of hydrogen ion.

The graph showing the fraction of species in the solution as a function of $\text{pH}$ is given below.

From the graph we can identify the $\text{pH}$ at which the $\left[{\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}\right]\text{=}\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]$

The fraction of dissociation will be 0.50 when the concentration of both the species will be equal.

The $\text{pH}$ corresponding to the equal concentration is approximately 6.4 from the graph.

(b)

Interpretation Introduction

Interpretation: The $\text{pH}$ at which the $\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]\text{=}\left[{\text{CO}}_{\text{3}}{}^{\text{2-}}\right]$ should be determined using the given graph.

Concept introduction:

Ocean acidification: The increase in concentration of carbon-dioxide in the atmosphere leads to ocean acidification. The amount is increasing day by day and this increase will lead to higher concentrations of dissolved ${\text{CO}}_{\text{2}}$ and as a result the amount of carbonic acid also will be higher.

The concentration of hydronium ion is a key factor for many biochemical reactions. So variation may affect the organisms in the oceans.

The relationship between ocean $\text{pH}$ and atmospheric ${\text{CO}}_{\text{2}}$ is that they are inversely proportional. The hydrogen ion concentration will be increased as the concentration of dissolved ${\text{CO}}_{\text{2}}$ increases and thus $\text{pH}$ will be decreased.

Answer to Problem 40GQ

The $\text{pH}$ at which the $\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]\text{=}\left[{\text{CO}}_{\text{3}}{}^{\text{2-}}\right]$ is approximately 10.3

Explanation of Solution

If the concentration of dissolved ${\text{CO}}_{\text{2}}$ is increased, then the $\text{pH}$ will be decreased as a result of the increase in concentration of hydrogen ion.

The graph showing the fraction of species in the solution as a function of $\text{pH}$ is given below.

From the graph we can identify the $\text{pH}$ at which the $\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]\text{=}\left[{\text{CO}}_{\text{3}}{}^{\text{2-}}\right]$

The fraction of dissociation will be 0.50 when the concentration of both the species will be equal.

The $\text{pH}$ corresponding to the equal concentration is approximately 10.3 from the graph.

(c)

Interpretation Introduction

Interpretation: The predominant species in the solution when the $\text{pH}$ is 8 should be determined.

Concept introduction:

Ocean acidification: The increase in concentration of carbon-dioxide in the atmosphere leads to ocean acidification. The amount is increasing day by day and this increase will lead to higher concentrations of dissolved ${\text{CO}}_{\text{2}}$ and as a result the amount of carbonic acid also will be higher.

The concentration of hydronium ion is a key factor for many biochemical reactions. So variation may affect the organisms in the oceans.

The relationship between ocean $\text{pH}$ and atmospheric ${\text{CO}}_{\text{2}}$ is that they are inversely proportional. The hydrogen ion concentration will be increased as the concentration of dissolved ${\text{CO}}_{\text{2}}$ increases and thus $\text{pH}$ will be decreased.

Answer to Problem 40GQ

The predominant species in the solution when the $\text{pH}$ is 8 is $\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]$.

Explanation of Solution

If the concentration of dissolved ${\text{CO}}_{\text{2}}$ is increased, then the $\text{pH}$ will be decreased as a result of the increase in concentration of hydrogen ion.

The graph showing the fraction of species in the solution as a function of $\text{pH}$ is given below.

When the $\text{pH}$ 8, ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}$ and ${\text{CO}}_{\text{3}}{}^{\text{2-}}$ will be minimum and the $\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]$ will be maximum.

From the graph it is clear that, the predominant species when the $\text{pH}$ is 8 is $\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]$.

(d)

Interpretation Introduction

Interpretation: The predominant species in the solution when the $\text{pH}$$7$ should be determined.

Concept introduction:

Ocean acidification: The increase in concentration of carbon-dioxide in the atmosphere leads to ocean acidification. The amount is increasing day by day and this increase will lead to higher concentrations of dissolved ${\text{CO}}_{\text{2}}$ and as a result the amount of carbonic acid also will be higher.

The concentration of hydronium ion is a key factor for many biochemical reactions. So variation may affect the organisms in the oceans.

The relationship between ocean $\text{pH}$ and atmospheric ${\text{CO}}_{\text{2}}$ is that they are inversely proportional. The hydrogen ion concentration will be increased as the concentration of dissolved ${\text{CO}}_{\text{2}}$ increases and thus $\text{pH}$ will be decreased.

Answer to Problem 40GQ

The predominant species in the solution when the $\text{pH}$ is 7 is $\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]$.

Explanation of Solution

If the concentration of dissolved ${\text{CO}}_{\text{2}}$ is increased, then the $\text{pH}$ will be decreased as a result of the increase in concentration of hydrogen ion.

The graph showing the fraction of species in the solution as a function of $\text{pH}$ is given below.

When the $\text{pH}$ is 7, the fraction of species is more for ${\text{HCO}}_{\text{3}}{}^{\text{-}}$.

From the graph it is clear that, the predominant species when the $\text{pH}$ is 7 is $\left[{\text{HCO}}_{\text{3}}{}^{\text{-}}\right]$.