Carboxylic Acids

Question 1

what are carboxylic acids?

Answer 1

organic molecules containing an -COOH functional group

Question 2

what does the name of a carboxylic acid show?

Answer 2

• the start of the name shows how many carbon atoms it has
• the end of the name is ‘-oic acid’ to show its a carboxylic acid

Question 3

formula for methanoic acid

Answer 3

HCOOH

Question 4

formula for ethanoic acid

Answer 4

CH3COOOH

Question 5

formula for propanoic acid

Answer 5

C2H5COOH

Question 6

formula for butanoic acid

Answer 6

C3H7COOH

Question 7

what is vinegar?

Answer 7

an aqueous solution of ethanoic acid

Question 8

how does vinegar form?

Answer 8

• it forms when the ethanol in wine undergoes microbial oxidation
• vinegar has a very sour, acrid taste because of the acidity of ethanoic acid
• red wine vinegar is the tastiest variety of vinegar

Question 9

how do carboxylic acids behave to form acids?

Answer 9

• an acid is an H+ donor, so like all other acids carboxylic acids can donate H+ to form a salt
• the carboxylic acid group (-COOH) loses its H+ and becomes negatively charged
• the name changes from ‘-oic acid’ in the carboxylic acid to ‘-oate’ in the salt

e.g. ethanoic acid -> ethanoate