Carboxylic acid

• What is the solubility of smaller carboxylic acids in water?

  They dissolve in all proportions
• Why do smaller carboxylic acids dissolve in water?

  They can hydrogen bond to water molecules
• How do carboxylic acids behave in water?

  They are weak acids and slightly dissociate
• What can carboxylic acids displace from carbonates?

  Carbon dioxide
• What stabilizes carboxylic acid salts?

  Delocalisation
• How does delocalisation affect the stability of carboxylic acid ions?

  It makes the ion more stable and likely to form
• What happens to C-O bond lengths in delocalised carboxylic acid ions?

  They have equal bond lengths
• How does increasing chain length affect carboxylic acid strength?

  It makes the acid less strong
• How do alkyl groups affect carboxylic acid strength?

  They are electron releasing, making acids weaker
• How does chlorine affect carboxylic acid strength?

  It is electron withdrawing, making acids stronger
• What is the naming convention for carboxylic acids?

  They end with -oic acid
• When is numbering not necessary in carboxylic acid names?

  When the acid group is at the end
• What is a -dioic acid?

  It has carboxylic acid groups on both ends
• What do carboxylic acids form when they react with alcohols?

  Esters and water
• What is required for the esterification reaction?

  A strong acid catalyst
• What is the general reaction for esterification?

  Carboxylic acid + alcohol → ester + water
• What is the yield of the esterification reaction?

  About 50%
• What happens during the hydrolysis of esters with acid?

  They form a carboxylic acid and an alcohol
• What is the effect of sodium hydroxide on esters during hydrolysis?

  It goes to completion and forms a salt
• What is the role of excess sodium hydroxide in ester hydrolysis?

  It ensures complete hydrolysis of the ester
• What is produced when ethyl benzoate is hydrolysed?

  Sodium benzoate and alcohol
• Why is sodium benzoate soluble in water?

  It is ionic
• Why is benzoic acid insoluble in water?

  It has a non-polar benzene ring
• What are fats and oils composed of?

  Esters of glycerol and long-chain carboxylic acids
• What do long-chain carboxylic acids produce when hydrolysed?

  Soap, glycerol, and fatty acids
• How do long-chain carboxylic acids act as soaps?

  They have hydrophilic and hydrophobic parts
• What is biodiesel made from?

  Methyl esters of long-chain carboxylic acids
• Why is biodiesel considered carbon-neutral?

  Carbon dioxide is absorbed during plant growth
• What factors affect the carbon-neutral status of biodiesel?

  Energy needed for production and processing
• What is the property of the long non-polar hydrocarbon chain in relation to water?

  It is hydrophobic and mixes with grease
• How does the hydrophobic property of the hydrocarbon chain benefit cleaning?

  It allows grease and water to mix and wash away
• What is glycerol also known as?

  Propane-1,2,3-triol
• Why is glycerol soluble in water?

  It forms hydrogen bonds very easily
• In what products is glycerol commonly used?

  Cosmetics, food, and glues
• How can vegetable oils be converted into biodiesel?

  By reaction with methanol in the presence of a catalyst
• What is biodiesel primarily composed of?

  Methyl esters of long chain carboxylic acids
• Why is biodiesel considered carbon-neutral?

  CO2 released was absorbed during plant growth
• What factors can affect the carbon neutrality of biodiesel?

  Energy needed for production from fossil fuels
• What is a potential issue with biodiesel production regarding land use?

  It may reduce land available for food production
• What is the chemical structure of ethanoic anhydride?

  CH3C(O)O-C(O)C(CH3)