Question

A) For this question and the three questions following it, we are going to assume that we will be working with another organic acid that is similar to Adipic Acid. We will call it Acid X. It is impure and we want to use the procedure of re-crystallization to purify it. Unfortunately it does not dissolve in water at all, either at high or low temperatures. However, it does dissolve apparently completely in boiling ethanol (BP of ethanol is 78.4^oC) whereas at room temperature there is no evidence that it dissolves at all. Will ethanol be a good solvent for re-crystallization of this adid? Why or why not?

B) If you did not know the identity of a pure sample of adipic acid that you were given but you knew the melting point of the sample was 152.1^oC and you knew it had the molecular formula C₆H₁₀O₄, what steps would you take to try to figure out what compound you had? Remember you have a computer available to you! What results did you find?

Answer 1

A). Ethanol is good solvent for recrystalisation because the condition for recrystalisation is : compound should be soluble in the solvent at high tempearature and insoluble at low temperature.

B) 1) check molecular formla: It matches with adipic acid

2) check given melting point : It also matches with adipic acid. So the given compound is adipic acid

3) Since melting point matches exactly with literature value. So the given acid is pure ( if it is impure there could have been deviation in melting point vale )