1. Lowering the Melting Point: This is the most common effect of impurities. The presence of impurities disrupts the regular arrangement of molecules in the crystal lattice, making it easier for the solid to transition into a liquid state. This results in a lower melting point compared to the pure compound.
2. Broadening the Melting Point Range: Pure compounds typically melt over a very narrow temperature range (usually less than 1°C). Impurities disrupt the crystal lattice, causing the melting process to occur over a wider temperature range. This means the melting point will start at a lower temperature and finish at a higher temperature, resulting in a broader melting point range.
In summary: Impurities typically lower the melting point and broaden the melting point range of an organic compound.
