Chapter 23, Problem 23.54AP

Interpretation Introduction

(a)

Interpretation:

The synthesis of alizarin yellow $\text{R}$ which is obtained by the reaction of aniline, salicyclic acid and other reagents is to be stated.

Concept introduction:

The chemical reaction in which an electrophile group is replaced by another functional group is called the electrophilic substitution reaction. When the electrophilic substitution happens on an aromatic ring such as benzene then the reaction is known as electrophilic aromatic substitution.

Friedal Craft acylation is an electrophilic aromatic substitution reaction. In this reaction, synthesis of monoacylated product takes place from the reaction between aromatic rings and acyl chlorides.

Interpretation Introduction

(b)

Interpretation:

The structure of alizarin yellow $\text{R}$ which is in the yellow form at $\text{pH}=\text{9}$ is to be drawn.

Concept introduction:

An acid is a substance which has a tendency to lose a hydrogen ion, ${\text{H}}^{+}$. Acidic solution turns blue litmus paper into red and is sour in taste. The $\text{pH}$ value ranges from $0$ to $7$. A base is a substance which has a tendency to release a hydroxide ion, ${\text{OH}}^{-}$ in water. Basic solutions turn red litmus paper into blue and are bitter in taste. The $\text{pH}$ value ranges from $8$ to $14$. Bases are slippery when touched.

Interpretation Introduction

(c)

Interpretation:

The structure of alizarin yellow $\text{R}$ at $\text{pH}>\text{12}$ is to be drawn.

Concept introduction:

An acid is a substance which has a tendency to lose a hydrogen ion, ${\text{H}}^{+}$. Acidic solution turns blue litmus paper into red and is sour in taste. The $\text{pH}$ value ranges from $0$ to $7$.

A base is a substance which has a tendency to release a hydroxide ion, ${\text{OH}}^{-}$ in water. Basic solutions turn red litmus paper into blue and are bitter in taste. The $\text{pH}$ value ranges from $8$ to $14$. Bases are slippery when touched.