Question

3. The melting point of unknown A was measured to be 110-120°C and unknown B was measured to be 105-109°C. What statement would make the best conclusion about the identity and purity of the product? (4 pts) A. Unknown A range of 110-120°C is the pure substance. Unknown B range of 105-109°C contains impurities. B. Unknown B range of 105-109°C is the pure substance. Unknown A range of 110-120°C contains impurities. C. Both Unknown A and B are pure substances. Since they have a small melting point range. D. All of the above. 4. Based on what you know about solubility and recrystallization, which of the following solid/solvent combinations can be used for recrystallization? (5 pts) A. Naphthalene/ water B. Urea/hexane C. Benzoic acid/ water D. All of the above

Answer 1

is 2°C (3) The Answer for this question is B. 108-109 °C Because the general the general range of melting point for pure substance But it is ok po Beco 5°C range Beyond that it is a impurity compound. so from the above the range of B is 5°C and A is loc so we considered A is impure and B is pere, Jubstance, (4) The Answer is Because all the verlaining are not pro dissolve in the soivent. But Benzoic acid will dissolve in het water and it is used to recrystallization process. C. Properly