Question

1. a student performs two melting point determinations on acrystalline product.
In one determination, the capillary tube contains a sample about1-2mm in height and the melting range is found to be 141 - 142degree C. In the other determination, the sample height is 4-5 mmand the melting range is found to be 141-145 degree C.
Explain the broader melting point range observed for the secondsample. The reported melting point for the compound is 143 degreeC.

2. Another student reports melting range of 136 - 138 degree Cfor the compound in Question 1 and mentions in her notebook thatthe rate of heating was about 12 degree/ min. NMR analysis of thisstudent's product does not reveal any impurites, explain the lowmelting point.