GCSE Chemistry - Esters #59

Esters are compounds with a COO functional group, known for their pleasant, fruity smells and volatility. They are used in perfumes and food flavorings. Esters are synthesized from carboxylic acids and alcohols, with ethyl ethanoate as an example, requiring an acid catalyst like concentrated sulphuric acid. The reaction produces water as a byproduct. The COO group, also called an ester link, connects the carboxylic acid and alcohol in the molecule.

What is the functional group present in esters that contributes to their distinctive properties?

• COO group

• OH group

• CH3 group

• NH2 group

Why are esters commonly used in perfumes and food flavorings?

• They are non-volatile

• They have pleasant, sweet or fruity smells

• They are colorless

• They have a strong metallic smell

Which two compounds are needed to synthesize ethyl ethanoate?

• Methanoic acid and methanol

• Butanoic acid and butanol

• Ethanoic acid and ethanol

• Propanoic acid and propanol

What is the role of concentrated sulphuric acid in the formation of esters?

• It acts as a catalyst

• It acts as a reactant

• It acts as a product

• It acts as a solvent

What is formed as a byproduct when a carboxylic acid and an alcohol react to form an ester?

• Hydrogen gas

• Carbon dioxide

• Water

• Oxygen