nitrogen compounds

• Carboxylic acids are compounds with a -COOH functional group and can be prepared by a series of different reactions.
• Ester hydrolysis by dilute alkali is an irreversible reaction forming a sodium carboxylate salt and alcohol.
• Carboxylic acids can be formed from the oxidation of primary alcohols and aldehydes by either acidified KCrO or acidified KMnO and re-use.
• The oxidising agents themselves get reduced causing the solutions to change colour in KCrO.
• In KMnO4, the purple manganate ions (MnO) are reduced to colourless Mn ions.
• Oxidation of primary alcohols and aldehydes gives carboxylic acids.
• Carboxylic acids can also be prepared from the hydrolysis of nitriles using either dilute acid or dilute alkali followed by acidification.
• Hydrolysis by dilute acid results in the formation of a carboxylic acid and ammonium salt.
• Hydrolysis by dilute alkali results in the formation of a sodium carboxylate salt and ammonia; acidification is required to change the carboxylate ion into a carboxylic acid.
• The -CN group at the end of the hydrocarbon chain is converted to a -COOH group during the hydrolysis of nitriles by either dilute acid or dilute alkali and acidification.
• Hydrolysis of esters is a reversible reaction and an equilibrium is established.
• Hydrolysis by dilute alkali is an irreversible reaction as all the ester is broken down to form a sodium carboxylate salt and an alcohol; acidification is required to change the carboxylate ion into a carboxylic acid.
• Hydrolysis of esters by either dilute acid or dilute alkali and heat followed by acidification will reform the alcohol and carboxylic acid.
• Carboxylic acids undergo a wide variety of reactions.
• Esters are formed from the condensation reaction between carboxylic acids and alcohols.
• Esters are compounds with an -COOR functional group and are characterised by their sweet and fruity smells.
• Esters are prepared from the condensation reaction between a carboxylic acid and alcohol with concentrated HSO as catalyst, this is also called esteriation.
• Ester hydrolysis by dilute acid is a reversible reaction forming carboxylic acid and alcohol.
• The sodium carboxylate (-COO) ion needs to get protonated by an acid (such as HCl) to form the carboxylic acid (-COOH).
• Carboxylic acids are reactive compounds which can undergo many types of reactions including: Redox reactions with reactive metals Neutralisation reactions with alkali Acid-base reactions with carbonates Esterification with alcohols Reduction by LiAlH + 4.
• Heating the ester under reflux with dilute alkali (eg, sodium hydroxide) is an irreversible reaction as the ester is fully hydrolysed, resulting in the formation of a sodium carboxylate salt which needs further acidification to turn into a carboxylic acid.
• When an ester is heated under reflux with dilute acid (eg, sulfuric acid), an equilibrium mixture is established as the reaction is reversible.
• The first part of the ester’s name comes from the alcohol and the second part of the name comes from the carboxylic acid, for example, Propanol and ethanoic acid will give the ester propyl ethanoate.
• Esters can be hydrolysed to reform the carboxylic acid and alcohol by either dilute acid or dilute alkali and heat.
• Carboxylic acids are weak acids that do not fully dissociate in water, the position of the equilibrium lies to the left.