Carboxylic Acids and Derivatives

Draw the displayed formula of ethanedioic acid.

The three acids, propanoic acid, methanoic acid and ethanedioic acid, can be distinguished using a combination of two chemical tests. Neither testing reagent is an acid–base indicator.

Identify two suitable testing reagents and complete Table 10.1 to show the observations from each test.

reagent 1 ........................................................ reagent 2 ........................................................

Table 10.1

When propanoic acid is treated with chlorine gas in the presence of ultraviolet light, a mixture of products is formed. One of these products is 2,2-dichloropropanoic acid.

Explain why 2,2-dichloropropanoic acid is stronger than propanoic acid. Refer to the structure of each compound in your answer.

Draw the intermediate organic compound M in the box.

Suggest suitable reagents and conditions for step 1 and step 2.

step 1

step 2

Identify the type of reaction in step 1 and step 2.

step 1

step 2

Complete the mechanism in Fig. 9.2 and include:

• all relevant dipoles ($\delta+$ and $\delta-$) and full electric charges (+ and -) on the species in box one and in box two
• all relevant lone pairs on the species in box one and in box two
• all relevant curly arrows to show the movement of electron pairs in box one and in box two
• the formula of the second product in box three.

Name this mechanism.

Benzoyl chloride, chlorobenzene and chloroethane differ in their rates of hydrolysis when each compound is added separately to water at $25^\circ\text{C}$.

Suggest the relative ease of hydrolysis of these three compounds.

Explain your answer.

Draw the intermediate organic compound M in the box.

Suggest suitable reagents and conditions for step 1 and step 2.

step 1 .................................................................................................................................

step 2 .................................................................................................................................

Identify the type of reaction in step 1 and step 2.

step 1 .................................................................................................................................

step 2 .................................................................................................................................

Complete the mechanism in Fig. 9.1 and include:

• all relevant dipoles ($\delta+$ and $\delta-$) and full electric charges ($+$ and $-$) on the species in box one and in box two
• all relevant lone pairs on the species in box one and in box two
• all relevant curly arrows to show the movement of electron pairs in box one and in box two
• the formula of the second product in box three.

Name this mechanism.

Benzoyl chloride, chlorobenzene and chloroethane differ in their rates of hydrolysis when each compound is added separately to water at $25\,^\circ\text{C}$.

Suggest the relative ease of hydrolysis of these three compounds.

Explain your answer.

......................................... ......................................... .........................................
hardest to hydrolyse                   easiest to hydrolyse

explanation ...............................................................................................................................

Describe and explain the relative acidities of chloroethanoic acid and ethanoic acid.

Phenyl 2-hydroxybenzoate is an antiseptic.

Complete the following table about the reactions of phenyl 2-hydroxybenzoate with the three reagents.

A series of experiments is carried out in which the reagent shown at the top of the column of the table is mixed, in turn, with each of the reagents at the side.
Complete the following table by writing in each box the formula of any gas produced.
Write x in the box if no gas is produced.
The first column has been completed as an illustration.

What reagents and conditions are required for step 3?

State the reagent and conditions needed to convert C back to B, the reverse of step 3.

A series of experiments is carried out in which the reagent shown at the top of the column of the table is mixed, in turn, with each of the reagents at the side.
Complete the following table by writing in each box the formula of any gas produced.
Write x in the box if no gas is produced.
The first column has been completed as an illustration.

What reagents and conditions are required for step 3?

State the reagent and conditions needed to convert C back to B, the reverse of step 3.