ESTERS [dchemlc]

what is the functional group of esters?

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Answer explanation

what are the two starting materials needed to produce an ester?

• alcohol

• carboxylic acid

• alkene

• alkane

• aldehyde

Answer explanation

e.g. Heating a mixture of ethanoic acid and ethanol with a few drops of concentrated sulfuric acid produces a liquid called ethyl ethanoate.

what is the catalyst used to produce esters from an alcohol and a carboxylic acid?

• conc. Sulphuric acid

• dil. Sulphuric acid

• conc. Sodium carbonate

• conc sodium hydroxide

Answer explanation

To make ethyl ethanoate,

Starting materials: ethanol and ethanoic acid

Catalyst: concentrated sulfuric acid

Conditions: heat

what is the name of the ester formed by reacting ethanol and ethanoic acid?

which of the following is not a use of an ester?

• perfumes

• food flavourings

• solvents

• liquor production

Answer explanation

name the alcohol used to produce methyl ethanoate.

what is the carboxylic acid needed to produce ethyl propanoate?

an esterification reaction can also be described as a condensation reaction. What is the molecule removed to form a bond between the alcohol and carboxylic acid?

• water

• hydrogen

• oxygen

• hydroxide

Answer explanation

The reaction is called esterification. It can also be described as a condensation reaction because water is made when two molecules are joined together.

why can't we heat a mixture of an alcohol and a carboxylic acid directly over the Bunsen burner?

• because the contents are flammable

• because the contents wont mix properly

• because the heat cant be controlled

• because it doesn’t have to be heated for the reaction to occur

Answer explanation

The mixture has to be heated, but not by a direct Bunsen flame because the contents of the tubes are flammable.

This reaction is reversible so to maximize the yield of ethyl ethanoate we often use pure ethanol and ethanoic acid. What would happen to the reaction if water was added to the mixture?

• amount of ethyl ethanoate produced decreases

• amount of ethyl ethanoate produced increases

• no change

• amount of ethyl ethanoate increases then decreases

Answer explanation

If water is added to the reactants, the system would want to shift to the left to consume the water and therefore decrease the amount of ethyl ethanoate made.