36. explain why mercury is rarely used in modern thermometers.

Brief Explanations:

Mercury is a toxic heavy metal. If a mercury - thermometer breaks, mercury vapor can be released. Mercury vapor is harmful when inhaled, and liquid mercury can cause skin contact issues. Also, mercury has a relatively high freezing point ((-38.83^{\circ}C)) and a high boiling point ((356.73^{\circ}C)). But the main reason for its disuse is its toxicity. In contrast, alcohol (e.g., ethanol) - based thermometers are less toxic. If broken, the alcohol evaporates more easily and is less of a health hazard.

Answer:

Mercury is rarely used in modern thermometers because it is a toxic heavy metal. If a mercury thermometer breaks, it can release mercury vapor (harmful when inhaled) or liquid mercury (can cause skin - related problems). Less toxic alternatives like alcohol - based thermometers are preferred.