Organic chemistry lab: separation of Benzoic Acid from Biphenyl, Crystallization

Question

Organic chemistry lab: separation of Benzoic Acid from Biphenyl, Crystallization and infrared spectroscopy
4)list the two reasons why biphenyl stays in the organic layer and doesn’t move to the basic aqueous layer
5) how much 6M HCL would you expect to use to neutralize the combined aqueous extracts (Don’t forget to consider the the Benzoic acid)?
6) what is the pKa of Benzoic acid? Rather than use a visual indicator for complete precipitation, one could use pH as an alternative. Given the pKa of Benzoic Acid what pH should you adjust the aqueous solution to when adding 6M HCL to the sodium benzoate solution to make sure all of the Benzoic acid is precipitated

List the two reasons why biphenyl stays in the organic layer and doesn't move to the basic aqueous layer. 4. How much 6M HCI would you expect to use to neutralize the combined aqueous extracts (don't forget to consider the benzoic acid)? 5. 6. What is the pKa of benzoic acid? Rather than use a visual indicator for complete precipitation, one could use pH as an alternative. Given the pKa of benzoic acid what pH should you adjust the aqueous solution to when adding 6M HCI to the sodium benzoate solution to make sure all of the benzoic acid is precipitated?

Explanation / Answer

4.

i) Biphenyl is a typical organic hydrocarbon.

ii) Biphenyl is neitheer acidic or basic, but Benzoic acid is acidic nature.

5. The mixture of benzoic acid and biphenyl can be separated by Dichloromethane and aqueous layer, the benzoic acid can be extract using NaOH, not HCl.

6. pKa of benzoic acid is 4.20 from the data base.

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.