Chapter 15, Problem 15.135QE

(a)

Interpretation Introduction

Interpretation:

Hydrogen atom that ionizes from the picric acid molecule has to be identified.

Concept Introduction:

The most common representation of oxy acid is given by ${\left(\text{OH}\right)}_m{\text{XO}}_n$. Here, the subscript $n$ holds importance because the strength of any oxyacid is dependent upon the value of non-hydrogen bonded $\text{O}$ atoms. The molecular structure of picric acid is given as follows:

(b)

Interpretation Introduction

Interpretation:

$\text{pH}$ of $0.100M$ of picric acid has to be calculated.

Concept Introduction:

The formula to calculate $\text{pH}$ is given as follows:

  $\text{pH}=-\text{log}\left[{\text{H}}_3{\text{O}}^{+}\right]$

(c)

Interpretation Introduction

Interpretation:

Balanced chemical equation corresponding to decomposition of picric acid has to be written.

Concept Introduction:

Refer to part (a).

(d)

Interpretation Introduction

Interpretation:

Whether substitution of ${\text{NO}}_{\text{2}}$ with ${\text{NH}}_{\text{2}}$ will increase or decrease the $K_{\text{a}}$ value along with the reason has to be explained.

Concept Introduction:

$K_{\text{a}}$ value signifies the extent of ionization of a given acid in an aqueous solution. The high $K_{\text{a}}$ value depicts greater acidic strength.