Chapter 17, Problem 42P

Interpretation Introduction

(a)

Interpretation:

The reaction of phenyl acetic acid with given reagents should be completed.

Concept Introduction:

Phenylacetic acid contains one −COOH group with molecular formula C₆ H₅ -CH₂ -COOH. Carboxylic acids react with base to form salt and water. This reaction is called as neutralization reaction. The reduction of carboxylic acid form carbonyl compounds and alcohols whereas reaction with alcohol forms ester.

Answer to Problem 42P

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{-CH}}_{\text{2}}\text{-COOH }+ {\text{NaHCO}}_{\text{3}} \to {\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{-CH}}_{\text{2}}{\text{-COO}}^{\text{-}}{\text{Na}}^{\text{+}}{\text{ + H}}_{\text{2}}{\text{O + CO}}_{\text{2}}$.

Explanation of Solution

The reaction of C₆ H₅ -CH₂ -COOH with sodium carbonate forms sodium salt of C₆ H₅ -CH₂ -COOH with water and carbon dioxide gas.

Interpretation Introduction

(b)

Interpretation:

The reaction of phenyl acetic acid with given reagents should be completed.

Concept Introduction:

Phenylacetic acid contains one −COOH group with molecular formula C₆ H₅ -CH₂ -COOH. Carboxylic acids react with base to form salt and water. This reaction is called as neutralization reaction. The reduction of carboxylic acid form carbonyl compounds and alcohols whereas reaction with alcohol forms ester.

Answer to Problem 42P

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{-CH}}_{\text{2}}\text{-COOH + NaOH }\to {\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{-CH}}_{\text{2}}{\text{-COO}}^{\text{-}}{\text{Na}}^{\text{+}}{\text{ + H}}_{\text{2}}\text{O }$.

Explanation of Solution

The reaction of C₆ H₅ -CH₂ -COOH with sodium hydroxide forms sodium salt of C₆ H₅ -CH₂ -COOH with water. This is a neutralization reaction as carboxylic acid reacts with base to form salt.

Interpretation Introduction

(c)

Interpretation:

The reaction of phenyl acetic acid with given reagents should be completed.

Concept Introduction:

Phenylacetic acid contains one −COOH group with molecular formula C₆ H₅ -CH₂ -COOH. Carboxylic acids react with base to form salt and water. This reaction is called as neutralization reaction. The reduction of carboxylic acid form carbonyl compounds and alcohols whereas reaction with alcohol forms ester.

Answer to Problem 42P

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{-CH}}_{\text{2}}{\text{-COOH + NH}}_{\text{3}}\to {\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{-CH}}_{\text{2}}{\text{-COO}}^{\text{-}}{\text{NH}}_{\text{4}}{}^{\text{+}}$.

Explanation of Solution

The reaction of C₆ H₅ -CH₂ -COOH with ammonia solution forms ammonium salt of C₆ H₅ -CH₂ -COOH that is ammonium phenyl acetate.

Interpretation Introduction

(d)

Interpretation:

The reaction of phenyl acetic acid with given reagents should be completed.

Concept Introduction:

Phenylacetic acid contains one −COOH group with molecular formula C₆ H₅ -CH₂ -COOH. Carboxylic acids react with base to form salt and water. This reaction is called as neutralization reaction. The reduction of carboxylic acid form carbonyl compounds and alcohols whereas reaction with alcohol forms ester.

Answer to Problem 42P

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{-CH}}_{\text{2}}{\text{-COOH + LiAlH}}_{\text{4}}{\text{/ H}}_{\text{2}}{\text{O}}_{}\to {\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}\text{-OH + LiOH + Al}{\left(\text{OH}\right)}_{\text{3}}$.

Explanation of Solution

The reaction of C₆ H₅ -CH₂ -COOH with lithium ammonium hydride followed by hydrolysis leads to formation of 2-phenylethanol. This is an example of reduction reaction and LiAlH₄ is a reducing agent.

Interpretation Introduction

(e)

Interpretation:

The reaction of phenyl acetic acid with given reagents should be completed.

Concept Introduction:

Phenylacetic acid contains one −COOH group with molecular formula C₆ H₅ -CH₂ -COOH. Carboxylic acids react with base to form salt and water. This reaction is called as neutralization reaction. The reduction of carboxylic acid form carbonyl compounds and alcohols whereas reaction with alcohol forms ester.

Answer to Problem 42P

C₆ H₅ -CH₂ -COOH + NaBH₄ / H₂ O (No reaction.

Explanation of Solution

NaBH4 with water is a weak reducing agent therefore it cannot reduce the carboxylic acid and no reaction is observed with it.

Interpretation Introduction

(f)

Interpretation:

The reaction of phenyl acetic acid with given reagents should be completed.

Concept Introduction:

Phenylacetic acid contains one −COOH group with molecular formula C₆ H₅ -CH₂ -COOH. Carboxylic acids react with base to form salt and water. This reaction is called as neutralization reaction. The reduction of carboxylic acid form carbonyl compounds and alcohols whereas reaction with alcohol forms ester.

Answer to Problem 42P

Explanation of Solution

Reaction of phenyl acetic acid with methanol in acidic medium as catalyst forms ester with water. This reaction is called as Fisher Esterification reaction.

Interpretation Introduction

(g)

Interpretation:

The reaction of phenyl acetic acid with given reagents should be completed.

Concept Introduction:

Phenylacetic acid contains one −COOH group with molecular formula C₆ H₅ -CH₂ -COOH. Carboxylic acids react with base to form salt and water. This reaction is called as neutralization reaction. The reduction of carboxylic acid form carbonyl compounds and alcohols whereas reaction with alcohol forms ester.

Answer to Problem 42P

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{-CH}}_{\text{2}}{\text{-COOH + H}}_{\text{2}}{\text{/ Ni}}_{}\to \text{No reaction }$.

Explanation of Solution

H₂ / Ni cannot reduce carboxylic acid group as it is reducing agent for alkene and alkyne to alkane. Hence no reaction will be observed here.