9. Carboxylic acids

Question 1

solubility of small COOH (physical properties)

Answer 1

very soluble in polar solvents e.g. H2O (like dissolves like)
Hydrogen bonds between COOH and H20

Question 2

solubility of large COOH (physical properties)

Answer 2

solubility decreases. only COOH forms Hydrogen bonds. more of the molecule is non polar

Question 3

weak acid equation (chemical properties)

Answer 3

CH3COOH + H20 () CH3COO- + H3O+

Question 4

reaction with metals ->

e.g. sodium + ethanoic acid ->

Answer 4

metal salt + hydrogen
2Na + 2CH3COOH -> 2CH3COONa + H2
sodium + ethanoic acid -> sodium ethanoate + hydrogen

Question 5

reaction with metal oxide (base) ->

e.g. magnesium oxide + methanoic acid ->

Answer 5

metal salt + water
MgO(s) + 2HCOOH -> Mg(HCOO)2(aq) + H2O(l)
magnesium oxide + methanoic acid -> magnesium methanoate + water

Question 6

reaction with metal hydroxide (alkali) ->

e.g. potassium hydroxide + propanoic acid ->

Answer 6

metal salt + water
KOH(aq) + CH3CH2COOH -> CH3CH2COOK + H2O
potassium hydroxide + Propanoic acid -> potassium propanoate + water

Question 7

reaction with metal carbonate (base) ->

e.g. sodium carbonate + methanoic acid ->

Answer 7

metal salt + water + carbon dioxide
NaCO3(s)+ 2HCOOH(aq) -> 2HCOONa(aq) + H2O(l) + CO2(g)
sodium carbonate + methanoic acid -> sodium methanoate + water + carbon dioxide