Question

Isolation synthesis and important properties of citric acid

Answer 1

Answer:

Lemons are traditional source of citric acid. citric acid is isolated from lemon juice by neutralization with NaOH and exchange process with the help of CaCl2 and sulfuric acid.

Explanation:

Isolation of citric acid from lemon juice.

• Add 10% w/v NaOH solution in juice till pH 8-9 for neutralization of citric  acid

      Citric acid + 3 NaOH --> Trisodium citrate + 3 H2O

• Vacuum filtrate the solution.

• Add CaCl2 solution and heat till the boiling.

     Trisodium citrate + 3 CaCl2 --> Tricalcium dicitrate + 6 NaCl

• Filter the settled trisodium citrate

• Add diluted sulfuric acid and boil the solution

     Tricalcium dicitrate + 3 H2SO4 --> 2 Citric acid + 3 Calcium sulfate

• Filter to remove insoluble CaSO4 from citric acid solution

• Boil the citric acid solution to evaporate water.

• Dry the citric acid crystal on tissue papers to remove water.

Properties of citric acid:

• Citric acid (C6H8O7) is a weak organic acid and naturally found in citrus fruits. It is a biochemical intermediate in the citric acid cycle.

• It works as a chemical chelator to bind metal ions, buffering agent.

• It is an emulsifying, antioxidant and acidifying agent.

• It can be used as stabilizer in commercially prepared juices.

• It can be used in the process to develop film.