Carboxylic acids (CnH2nO2)

Question 1

Oxidation of alkenes. EXAMPLE AND CONDITIONS.

Answer 1

Propene+[O]—>Ethanoic acid+CO₂+H2O.
Conditions= Hot concentrated H+/KMnO4(VII).

Question 2

Oxidation of primary alcohols. EXAMPLE AND CONDITIONS.

Answer 2

Ethanol+[O]—>Ethanol+[O]—>Ethanoic acid.
Conditions= H+/KMnO4(VII) or H+/K₂Cr₂O7(VI).

Question 3

Name all 5 carboxylic acids production methods.

Answer 3

1.Oxidation of alkenes.
2.Oxidation of primary alcohols.
3.Oxidation of aldehydes.
4.Hydrolysis of esters.
5.Hydrolysis of nitriles.

Question 4

Hydrolysis of esters. EXAMPLE AND CONDITIONS.

Answer 4

Propyl ethanoate+H2O—>Propanol+Ethanoic acid.
Conditions= Dilute HCl(aq) or Dilute NaOH(aq).

Question 5

Oxidation of aldehydes. EXAMPLE AND CONDITIONS.

Answer 5

Propanal+[O]—>Propanoic acid.
Conditions= H+/KMnO4(VII) or H+/K₂Cr₂O7(VI).

Question 6

Hydrolysis of esters with dilute NaOH(aq). What is the additional step required to form carboxylic acid and why is it needed?

Answer 6

Acidification, because NaOH(aq) will react with the carboxylic acid to form Na Carboxylate salt so acidification is required to form carboxylic acid once again.

Question 7

Hydrolysis of nitriles. EXAMPLE AND CONDITIONS.

Answer 7

Propanenitrile+H2O—>Propanoic acid+NH4Cl…when reacted with dilute HCl(aq).
Propanenitrile+H2O—>Sodium propanoate+NH3…when reacted with dilute NaOH(aq)…acidification step required to form propanoic acid once again.

Question 8

Name all 5 carboxylic acid reactions.

Answer 8

1.Metal+Carboxylic acid—>Metal salt+H2.
2.Carboxylic acid+Base—>Metal salt+H2O.
3.Metal carbonate+Carboxylic acid—>Metal salt+CO₂+H2O.
4.Esterification.
5.Reduction of carboxylic acid to primary alcohol.

Question 9

Metal+Carboxylic acid—>Metal salt+H₂. EXAMPLE.

Answer 9

Na+CH3CH2COOH—>(CH3CH2COO)Na+H₂.

Question 10

Carboxylic acid+Base—>Metal salt+H2O. EXAMPLE.

Answer 10

Propanoic acid+NaOH—>(CH3CH2COO)Na+H2O.

Question 11

Metal carbonate+Carboxylic acid—>Metal salt+CO₂+H2O. EXAMPLE.

Answer 11

MgCO3+Propanoic acid—>(CH3CH2COO)₂Mg+CO₂+H2O.

Question 12

Esterification (condensation reaction). EXAMPLE AND CONDITIONS.

Answer 12

Propanol+Propanoic acid—>Propyl ethanoate+H2O.
Conditions= Heat and concentrated H2SO4.

Question 13

Reduction of carboxylic acid to primary alcohol. EXAMPLE AND CONDITIONS.

Answer 13

Propanoic acid+2[H]—>Propanal+2[H]—>Propanol.
Conditions= LiAlH4(ether)

Question 14

Test for alcohols vs carboxylic acids.

Answer 14

Alcohols wont react with metals and metal carbonates.
Carboxylic acids will react with metals to form metal carboxylate salts and hydrogen.
Carboxylic acids will react with metal carbonates to form metal carboxylate salts,CO2, and water.