Q.Distinguish between a conductor and an insulator in terms of the free and bound charges present in each.

In a conductor, the outermost electrons of each atom are loosely bound and free to move throughout the entire body of the material, forming a mobile "sea" of delocalised free charges past the fixed positive ion cores -- this is why conductors conduct electricity, and why an external field causes free charges to redistribute (electrostatic induction) until the interior field is cancelled.

In an insulator (dielectric), electrons remain tightly bound to their own individual parent atoms or molecules and cannot travel through the bulk of the material at all. An external field can still displace or reorient these bound charges locally (Section 2.11, polarization), but never move them any appreciable distance through the material -- which is why insulators do not conduct electricity.

Contrast the mobility of the outer electrons in each type of material.

• Saying insulators have "no charges at all" -- they have plenty of charge, it simply cannot move freely through the bulk.
• Confusing "free charge" (able to move through the material) with "net charge" (the total charge a body carries) -- these are different ideas.