If a pure compound X has a melting range of 128-129°C, what would NOT account for a melting range of 119-129°C in a sample of compound X?

The pure compound X has a defined melting range of 128-129°C, indicating that its melting point is consistent and narrow. When a sample exhibits a melting range of 119-129°C, it implies that the sample may contain impurities or other discrepancies affecting its thermal properties.

A soluble impurity would typically lower the melting point of the pure compound, resulting in a broadening and shifting of the melting range. However, the presence of a soluble impurity contributing to this observed melting range would not be the only cause. Other factors, such as weighing inaccuracies or variations in heating rates, can also impact the accuracy and observation of the melting point.

Inaccurate sample weighing could result from an insufficient amount of compound being used, leading to a sample that might not form a consistent solid. Incorrect heating rates could cause uneven distribution of heat, impacting the melting point observed due to gradual energy absorption. Contamination during the procedure could introduce foreign substances or compounds into the sample, further impacting the observed melting behavior.

However, the introduction of a soluble impurity would generally lower and broaden the melting range, while the other options are less directly correlated with simply shifting or broadening the melting point solely via soluble impurities. Thus, the melting range observed could be influenced