What is the best practice for evaluating the odor of a chemical?

Using your hand to gently waft the smell toward you is the best practice for evaluating the odor of a chemical because it minimizes the risk of exposure to potentially harmful fumes. This technique involves creating a gentle airflow that carries the odor toward your nose without placing your face directly over the container. By wafting, you can cautiously assess the odor while keeping a safe distance, thus protecting your respiratory system from any adverse effects associated with inhaling concentrated vapors.

The other methods, such as sniffing directly from the container or placing your nose close to the chemical, pose a higher risk of inhaling harmful chemicals in greater concentrations. Covering your nose with a mask may provide some protection but does not allow you to accurately evaluate the odor, which is essential for certain laboratory procedures. Therefore, wafting represents a balance between safety and the need to perceive the chemical's characteristics.