Which is the stronger acid: chloric(I) acid HClO with a K a of 3 . 7 × 10 - 8 mol dm - 3 , or hydrocyanic acid HCN with a K a of 4 . 9 × 10 - 10 mol dm - 3 . Then explain how the K a value enables you to decide.

K a is acid dissociation constant and represents the strength of the acid. pK a is the - log of K a . They have an inverse relationship. Larger the K a , smaller the pK a and stronger the acid. we have given, chloric I acid HClO with a K a of 3 . 7 × 10 - 8 mol dm - 3 , Hydrocyanic acid HCN with a K a of 4 . 9 × 10 - 10 mol dm - 3 . From the above given values of K a , chloric I acid has more K a value, so that is stronger acid than hydrocyanic acid.

EASY

AS and A Level

IMPORTANT

Earn 100

Acyl chlorides and carboxylic acids can both be used to prepare esters. Describe what you see happen in this reaction i.e. the formation of phenyl benzoate directly from an acyl chloride.

Important Questions on Carboxylic Acids and their Derivatives

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 26 - Carboxylic Acids and their Derivatives>BEFORE YOU START>Q 1

Which is the stronger acid: chloric(I) acid

(HClO)

with a

K_{a}

3.7 \times 10^{- 8} mol {dm}^{- 3}

, or hydrocyanic acid

(HCN)

with a

K_{a}

4.9 \times 10^{- 10} mol {dm}^{- 3}

. Then explain how the

K_{a}

value enables you to decide.

MEDIUM

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 26 - Carboxylic Acids and their Derivatives>TRANS-FATTY ACIDS>Q •

Why do the makers of margarines often use trans-fatty acids to make their products?

MEDIUM

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 26 - Carboxylic Acids and their Derivatives>EXAM-STYLE QUESTIONS>Q 1

Acyl chlorides and carboxylic acids can both be used to prepare esters. Describe two advantages that acyl chlorides have over carboxylic acids in the preparation of esters in industry.

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 26 - Carboxylic Acids and their Derivatives>EXAM-STYLE QUESTIONS>Q 2

Give the name and formula of a reagent that can be used to prepare butanoyl chloride from butanoic acid.

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 26 - Carboxylic Acids and their Derivatives>EXAM-STYLE QUESTIONS>Q 2

Write a balanced equation for the reaction to prepare butanoyl chloride from butanoic acid.

MEDIUM

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 26 - Carboxylic Acids and their Derivatives>EXAM-STYLE QUESTIONS>Q 2

Butanoic acid is a weaker acid than

2

-chlorobutanoic acid. Explain why.

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 26 - Carboxylic Acids and their Derivatives>EXAM-STYLE QUESTIONS>Q 2

Draw the skeletal formula of

2

-chlorobutanoic acid.

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 26 - Carboxylic Acids and their Derivatives>EXAM-STYLE QUESTIONS>Q 2

Name a chloro-substituted butanoic acid that is a stronger acid than

2

-

chlorobutanoic acid.

Acyl chlorides and carboxylic acids can both be used to prepare esters. Describe what you see happen in this reaction i.e. the formation of phenyl benzoate directly from an acyl chloride.

Important Questions on Carboxylic Acids and their Derivatives

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