Chapter 19, Problem 19.141P

(a)

Interpretation Introduction

Interpretation:

Species among ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}$, ${\text{HCO}}_{\text{3}}^{\text{-}}$, ${\text{CO}}_{\text{3}}^{\text{2-}}$ having highest concentration at $\text{pH}\text{=}\text{8}\text{.5}$ has to be calculated.

Concept introduction:

$pH$:

$\text{pH}$ is a scale used to specify the acidity or basicity a solution.  It ranges from $0-14$.  $\text{pH}$ $7.0$ is considered as neutral solution, $\text{pH}$ more than $7.0$ is taken as basic solution whereas $\text{pH}$ less than $7.0$ is considered as acidic solution (at ${\text{25}}^{\text{ο}}\text{C}$).  It is the measurement of activity of free ${\text{H}}^{\text{+}}$ and ${\text{OH}}^{\text{-}}$ in solution.

$p{K}_a$:

$p{K}_a$ is the negative log of acid dissociation constant that determines the strength of the acid. Lower the $p{K}_a$ value stronger is the acid.

${\text{pK}}_{\text{a1}}$ is the 1^st dissociation constant for the acid and ${\text{pK}}_{\text{a2}}$ is the 2^nd dissociation constant of the acid.

(b)

Interpretation Introduction

Interpretation:

At $\text{pH}\text{=}\text{8}\text{.5}$ the concentration ratio of $\frac{\left[{\text{HCO}}_{\text{3}}^{\text{-}}\right]}{\left[{\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}\right]}$ and $\frac{\left[{\text{CO}}_{\text{3}}^{\text{2-}}\right]}{\left[{\text{HCO}}_{\text{3}}^{\text{-}}\right]}$ has to be calculated.

Concept introduction:

$pH$:

$\text{pH}$ is a scale used to specify the acidity or basicity a solution. It ranges from $0-14$. $\text{pH}$ $7.0$ is considered as neutral solution, $\text{pH}$ more than $7.0$ is taken as basic solution whereas $\text{pH}$ less than $7.0$ is considered as acidic solution (at ${\text{25}}^{\text{ο}}\text{C}$). It is the measurement of activity of free ${\text{H}}^{\text{+}}$ and ${\text{OH}}^{\text{-}}$ in solution.

$p{K}_a$:

$p{K}_a$ is the negative log of acid dissociation constant that determines the strength of the acid. Lower the $p{K}_a$ value stronger is the acid.

${\text{pK}}_{\text{a1}}$ is the 1^st dissociation constant for the acid and ${\text{pK}}_{\text{a2}}$ is the 2^nd dissociation constant of the acid.

Henderson-Hasselbalch Equation:

This equation is used to determine the $\text{pH}$ of a buffer solution.  ${\text{K}}_{\text{a}}$ is the given quantity which is acid dissociation constant. It is done for a given concentration of acid and its conjugate base.

  $\text{pH=}{\text{pK}}_{\text{a}}\text{+}\text{log}\frac{\left[\text{salt}\right]}{\left[\text{acid}\right]}$

(c)

Interpretation Introduction

Interpretation:

Reason for lower $\text{pH}$ at deep sea level has to be interpreted.

Concept introduction:

$pH$:

$\text{pH}$ is a scale used to specify the acidity or basicity a solution. It ranges from $0-14$. $\text{pH}$ $7.0$ is considered as neutral solution, $\text{pH}$ more than $7.0$ is taken as basic solution whereas $\text{pH}$ less than $7.0$ is considered as acidic solution (at ${\text{25}}^{\text{ο}}\text{C}$). It is the measurement of activity of free ${\text{H}}^{\text{+}}$ and ${\text{OH}}^{\text{-}}$ in solution.

Photosynthesis:

The process of photosynthesis occurs in plants for their survival.  In this process carbon dioxide is absorbed from nature and oxygen is released to nature by plants.  Sunlight is the main important component for photosynthesis to occur.  Here glucose is formed.

  $\text{6}{\text{CO}}_{\text{2}}\text{+}\text{6}{\text{H}}_{\text{2}}\text{O}\stackrel{\text{sunlight}}{\rightleftarrows }{\text{C}}_{\text{6}}{\text{H}}_{\text{12}}{\text{O}}_{\text{6}}\text{+}{\text{6O}}_{\text{2}}$

Respiration:

Respiration is a biochemical process in which in the cells of organisms energy is evolved due to reaction between oxygen and glucose and by this process carbon dioxide is released along with water and ATP

  ${\text{C}}_{\text{6}}{\text{H}}_{\text{12}}{\text{O}}_{\text{6}}\text{+}{\text{6O}}_{\text{2}}\underset{}{\rightleftarrows }\text{6}{\text{CO}}_{\text{2}}\text{+}\text{6}{\text{H}}_{\text{2}}\text{O}\text{+}\text{ATP}$