Question

Which is the least conductor of heat?
A. Gold
B. Platinum
C. Silver
D. Lead

Answer 1

Hint:Conductor is defined as the material which permits the electrons to flow through it. The common conductors are copper, copper covered steel, high strength copper alloys and aluminium. The conductor is used to conduct the flow of electricity easily. While an insulator is the material which does not allow the passing of electricity through it.

Complete answer:
The conductor of heat means that if a side of the material is heated then the other side will also get heated to the temperature by transferring the heat through the material. The least conductor of heat means that if the particular material is heated from one end then it will not transfer the heat to the other side of the material.
Gold is metal which contains free electrons that can transfer the energy which is present in it, in the form of heat rapidly. The electrons in them can be delocalized. If we apply an electric voltage to it then the electric field within the metal triggers the movement of the electrons, by making them shift from one end to another.
Platinum is a good conductor of heat because the particles of it are closely packed to each other in metal lattice. The energy which is required is based on the amount or number of electrons which are present in the valence shell. As it has only one valence electron according to electronic configuration so it is also a good conductor of heat.
Silver is considered to be the good conductor of heat because it also contains free electrons in it. It has high electron mobility.
Lead is considered to be the conductor of heat but a poor conductor of heat because it does not allow enough electrons to pass through it easily.

Hence the correct option for this question is option ‘d’.

Note:
Lead is not only a poor conductor of heat but also a poor conductor of electricity as it does not allow the passing of ions through it easily. It is a ductile, malleable metal. This metal is also resistant to corrosion. It is used in batteries manufactured only because of its corrosion property not because of being a conductor of heat.