Alcohols, Carboxylic Acids and Esters: Answers

What functional group is present in the alcohol homologous series?

Alcohols have the -OH (hydroxyl) functional group.

What products are formed when propanol is reacted with oxygen in a combustion reaction?

Propanol reacts with oxygen in a combustion reaction to form carbon dioxide and water.

What is formed when ethanol is heated with potassium dichromate in the presence of dilute sulfuric acid?

When ethanol is heated with potassium dichromate in the presence of dilute sulfuric acid, ethanoic acid is formed. The sulfuric acid acts as a catalyst in the reaction.

What conditions are needed for producing ethanol by reacting ethene with steam? What advantage does this method have over the production of ethanol by fermentation of glucose?

The reaction of ethene with steam to form ethanol requires a phosphoric acid catalyst, temperatures of approximately 300 degrees Celsius and pressures of 60-70 atmospheres. The advantage of this process (compared to the fermentation of glucose) is that the process is cheaper and the reaction has 100% atom economy which means that ethanol is the only product so it does not need to be purified.

What are the functional groups present in carboxylic acids and esters?

Carboxylic acids have the ‘-COOH’ functional group and esters have the ‘-COO’ functional group.

What is formed when propanoic acid reacts with potassium?

When a carboxylic acid reacts with a metal, a salt and hydrogen are produced. Propanoic acid reacts with potassium to form potassium propanoate and hydrogen.

What is formed when methanoic acid reacts with calcium carbonate?

When a carboxylic acid reacts with a metal carbonate, a salt, carbon dioxide and water are produced. Methanoic acid reacts with calcium carbonate to form calcium methanoate, water and carbon dioxide.

What kind of catalyst is used for forming an ester from reacting an alcohol with a carboxylic acid?

An acid catalyst is used for esterification reactions (where an alcohol and carboxylic acid react to form an ester and water). Concentrated sulfuric acid is commonly used as the acid catalyst.

Name the ester that is formed when butanoic acid is reacted with methanol.

Remember that for naming esters, the first part of the name comes from the alcohol and the second part of the name comes from the carboxylic acid. Therefore, the ester formed between butanoic acid and methanol will be called methyl butanoate.