Carboxylic Acids Flashcards
What are the 2 polar regions in the -COOH group?
C–O and O-H
Why are carboxylic acids solube in water?
They can form H bonds with water molecules.
Lone pair on O of double bond
Delta positive H of -OH group
How does solubility of carboxylic acids change?
Less soluble as the carbon chain gets longer as the increase in e- means non-polar C-C bond have greater effect on overall polarity of the molecule
What are the chemical properties of carboxylic acid?
Partially dissociate in water = weak acid. Forms Carboxylate ion (eg ethanoate) and H+
What do carboxylic acids react with metals to form?
A carboxylic salt and Hydrogen. This is a redox reaction. Metal and H change oxidation numbers
What would you observe when carboxylic acid reacts with a metal?
Metal dissolves away and bubbles of gas forming
What is the neutralisation reaction of carboxylic acids with metal oxides? Give an example
carboxylate salt + water
2CH3COOH(aq) + K2O(s) —> 2CH3COO-K+ (aq) +H20 (l)
Observation: Dissolving of metal oxide
Salt: Potassium ethanoate
What is the neutralisation reaction of carboxylic acids with alkalis? Give an example
Carboxylate salt + water
2HCOOH(aq) + Mg(OH)2 (s) —> (HCOO-)2Mg2+ (aq) + 2H20(l)
Observation: dissolving of metal hydroxide
Salt: Magnesium methanoate
What is the neutralisation reaction of carboxylic acids with metal carbonates?
Carboxylate salt + water + carbon dioxide
2CH3CH2CH2COOH (aq) + Na2CO3 (s) —> 2CH3CH2CH2COO- Na+ + H2O (l) + CO2 (g)
Observation: Metal carbonate dissolves and bubbles of gas
Salt: Sodium butanoate
How do we test for carboxyl group?
Reacting with carbonates as they are the only organic compound sufficiently acidic enough to react with carbonates
How do we distingusish between carboxyls and phenol?
React with carbonates. No effervescence when phenol reacts as it isn’t acidic enough. There is effervescence when carboxylic acid reacts as it is acidic enough
