Carboxylic acids Flashcards
What is the functional group of carboxylic acids?
-COOH.
Why is carboxylic acids soluble in water?
A carboxylic acid has both C=O and O-H bonds which are polar. The polarity of these bonds allows the carboxylic acid to form hydrogen bonds with water molecules.
How does solubility of carboxylic acids vary with the length of the carbon chain?
As the carbon chain gets longer, the solubility of the carboxylic acid decreases. This is because the carbon chain is non-polar.
Why are carboxylic acids described as weak acids?
Carboxylic acids only partially dissociates; this is because equilibrium lies to the left.
If there is partial dissociates, there will be less hydrogen ions in solution. A factor that determines acidity is the concentration of hydrogen ions in solution. If there is less hydrogen ions, acidity is weak.
What ions are formed when a carboxylic acid dissociates?
A hydrogen ion and a carboxylate ion.
What is formed when a carboxylic acid reacts with a metal hydroxide?
Salt (metal carboxylate) and water
What is formed when a carboxylic acid reacts with a metal oxide?
Salt (metal carboxylate) and water
What is formed when a carboxylic acid reacts with a metal?
Salt (metal carboxylate) and hydrogen gas
What is formed when a carboxylic acid reacts with a metal carbonate?
Salt (metal carboxylate), carbon dioxide, water
Propanoic acid reacts with sodium hydroxide. What are the products formed?
Sodium propanoate and water
Pentanoic acid reacts with ammonium carbonate. What is formed?
Ammonium pentanoate, carbon dioxide and water
What is the functional group of acyl chlorides?
-COCl
How to name acyl chlorides?
The name of the molecule ends in -‘oyl chloride’. The start of the name is determined by the number of carbons in the molecule.
An acyl chloride with 4 carbons is called butanoyl chloride.
How can acyl chlorides be formed with carboxylic acids?
React carboxylic acids with thionyl chloride (SOCl2). This produces acyl chloride, sulphur dioxide and hydrochloric acid.
What is formed when reacting acyl chloride and water?
Carboxylic acid and hydrochloric acid.