What result might indicate the formation of an ester in a reaction?

The formation of an ester in a reaction is commonly indicated by a fruity smell and a change in physical properties. This is characteristic because esters are known for their distinctive and often pleasant odors, which are reminiscent of fruit. When an ester is synthesized, such as in the reaction of a carboxylic acid with an alcohol, the reaction may also lead to variations in physical properties such as boiling point and solubility, which can be observed as the reaction progresses.

While changes in color, gas release, or temperature fluctuations can potentially indicate different types of chemical reactions, they are not specific indicators of ester formation. The fruity smell is a hallmark of ester synthesis, making it a reliable result to confirm the reaction's progression toward producing an ester.