Question

Which of the following is an important consideration when designing an acid-base extraction protocol for an amphoteric compound?

A. the mass to charge ratio of the compound (m/z)

B. the stretching frequency of the compound

C. the volatility of the compound

D. the isoelectric point of the compound

20. A compound with a very low K_ow is best described as being

A. lipophilic

B. hydrophobic

C. problematic

D. hydrophilic

21. A basic compound has a pK_a of 0.3. Which of the following statements is true?

A. The compound will be in its salt form at a pH of 3.

B. The compound is a very weak base.

C. The compound is amphoteric.

D. The compound cannot be extracted into water.

Answer 1

19. The correct answer is an option D.

Explanation: The isoelectric point is the pH at which the net charge on the molecule = 0 is perfectly suitable for the amphoteric molecule.

20. The correct answer is an option D.

Explanation: Water organic solvent, If Kow (i.e. partition coefficient of the compound between aqueous and organic layers) is less then the equilibrium shifts towards the left side. Hence, the compound is said to be hydrophilic.

21. The correct answer is an option B.

Explanation: The less pKa value (i.e 0.3) indicates that the compound has more value of Ka, then the compound is said to be a weak base.