Question

Name a liquid which is a good conductor of heat.
A. Mercury
B. Bromine
C. Iodine
D. Alcohol

Answer 1

Hint: A conductor can be termed as a good conductor based on the ease of flow of charge. Metals are excellent conductors. Any material having characteristics similar to that of metal will be a good charge carrier. Among the options filter the one with the characteristics of a good charge carrier for the correct answer.


Complete step by step solution:
The determination of good conduction of heat of a liquid depends upon its thermal conductivity. Thermal Conduction is the transport of energy due to the random motion of molecules across a temperature gradient. In Simple terms, thermal conductivity is the measure of a material’s ability to conduct heat. Thermal Conductivity is denoted by λ or k.
In the International System of Units, Thermal Conductivity is measured in watts per meter-Kelvin (W/(m.K)).
The thermal conductivity of the substances given above is as follows:-

Substance Used	Thermal Conductivity at 25°C in (W/(m.K))
Mercury	8.395
Bromine	0.120
Iodine	0.449
Ethyl Alcohol	0.167

Mercury is a heavy, silvery-white common metal which is also the only chemical element that stays liquid at room temperature and pressure. It is represented by the symbol Hg and the atomic number is 80.
Mercury has the highest Thermal Conductivity in comparison to Iodine, Bromine, and Alcohol.

Therefore, the correct option is A i.e., Mercury.

Additional Information:
1. Under standard conditions, Iodine is a solid, lustrous purple-black non-metal.
2. Alcohol evaporates quickly in presence of heat.
3. Bromine is the only non-metallic element that stays liquid at room temperature.

Note:
Mercury is a toxic liquid and because of its high toxicity, it is slowly being phased out of use from medical equipment such as thermometers. Mercury is used in thermometers not specifically because of heat conduction but because of its shiny appearance, high coefficient of expansion and high boiling point which makes it fit to measure high temperatures.