Esters are formed from carboxylic acids and alcohols in the presence of conc. sulfuric acid. Which statement correctly describes this esterification?

Master NCEA Level 3 Organic Chemistry Reaction Schemes. Prepare with multiple choice questions, complete with hints and detailed explanations. Ace your exam with our comprehensive tools!

Multiple Choice

Esters are formed from carboxylic acids and alcohols in the presence of conc. sulfuric acid. Which statement correctly describes this esterification?

This is the Fischer esterification: an acid-catalyzed condensation between a carboxylic acid and an alcohol to give an ester and water, with concentrated sulfuric acid acting as both catalyst and dehydrating agent. The strong acid protonates the carbonyl oxygen of the carboxylic acid, making the carbonyl carbon more susceptible to nucleophilic attack by the alcohol. After a proton shuffle and a tetrahedral intermediate, water is lost and a protonated ester forms, which then loses a proton to give the neutral ester. Because the reaction is reversible, removing water or using excess alcohol helps push the equilibrium toward the ester. So the statement describing this process correctly is that esters are formed from carboxylic acids and alcohols in the presence of concentrated sulfuric acid. The alternatives aren’t describing this reaction: water is produced as a byproduct but not instead of the ester, and ketones or amides are not formed under these conditions.

This is the Fischer esterification: an acid-catalyzed condensation between a carboxylic acid and an alcohol to give an ester and water, with concentrated sulfuric acid acting as both catalyst and dehydrating agent. The strong acid protonates the carbonyl oxygen of the carboxylic acid, making the carbonyl carbon more susceptible to nucleophilic attack by the alcohol. After a proton shuffle and a tetrahedral intermediate, water is lost and a protonated ester forms, which then loses a proton to give the neutral ester. Because the reaction is reversible, removing water or using excess alcohol helps push the equilibrium toward the ester.

So the statement describing this process correctly is that esters are formed from carboxylic acids and alcohols in the presence of concentrated sulfuric acid. The alternatives aren’t describing this reaction: water is produced as a byproduct but not instead of the ester, and ketones or amides are not formed under these conditions.

More practice questions