What is the boiling temperature of mercury and alcohol?
- 357°C and 78 °C
- -39°C and -115 °C
- 100°C and 120 °C
- 100°C and 90 °C
1 Answer
The correct answer is A = 357°C and 78 °C
The vacuum in the other bulb allows free movement of the alcohol and mercury. It is the alcohol which measures the temperature; the mercury indicates the temperature reading on both scales. This is unlike a normal mercury thermometer, in which the expansion and contraction of mercury itself indicates temperature.If the purpose of the thermometer is to use it during the preparation of food, mercury could be used because of its high boiling point (356,7°C). If alcohol was used for this application, it would start to boil at around 78°C.
Alcohol thermometers are also inexpensive and durable. They are typically not as accurate as mercury thermometers because of the alcohol's susceptibility to evaporation, polymerization potential and capillary separation. Their primary advantage is safety to humans and the environment.
Alcohol thermometers are used rather than mercury thermometers in very cold regions because alcohol has a lower freezing point than mercury. Pure ethanol freezes at -115 degrees C, while mercury freezes at -38 degrees C.Since 2001, 20 states have banned mercury “fever thermometers” for medical use, and regulations tighten every year. Many pharmacies now carry only sterile digital replacements or the less accurate ones with red glop in the bulb.