Arrange the following materials in the increasing order of conductivi…

The correct answer is Option (3) → (D), (B), (A), (C)

Conductivity is the ability of a material to carry an electric current. Materials fall into clear groups:

• Insulators (glass, Teflon) have almost no free charge carriers, so their conductivity is extremely low.

• Graphite is a non-metal that conducts through the delocalised electrons in its layers, but far less well than metals.

• Metals have a sea of free electrons and the highest conductivity. Among metals, silver is the best conductor, well ahead of sodium.

Combined order:

    \( \displaystyle \text{insulator} < \text{graphite} < \text{sodium} < \text{silver} \)

The conductivities at 298.15 K show the same order:

• (D) Teflon: 1.0 × 10⁻¹⁸ S m⁻¹ (insulator), first

• (B) Graphite: 1.2 × 10 S m⁻¹, second

• (A) Sodium: 2.1 × 10³ S m⁻¹, third

• (C) Silver: 6.2 × 10³ S m⁻¹, the best conductor, fourth

Shortcut: Teflon (D) is the poorest conductor and silver (C) the best. Only Option (3) starts with (D) and ends with (C).

NCERT (2026-27 edition):
Conductance of Electrolytic Solutions – …