Which is among the following has lowest thermal conductivity?

Which is among the following has lowest thermal conductivity?

a. Liquid
b. Gases
c. Pure metal
d. Non-metallic crystalline and amorphous substance

Correct Answer : b. Gases

Explanation :

Conduction takes place from one side of solid to another without any appreciable displacement of molecules of the solid which are very close to each other. As the distances between molecules of gases are more, they are bad at heat transfer. Thus they have lowest thermal conductivity.