Question

Which of the following does not conduct electricity?

• A. Fused NaCl
• B. Solid NaCl
• C. Brine solution
• D. Copper

Answer 1

The correct option is B

Solid NaCl

B

• In order to conduct electricity, the substance must have free electrons or ions.
• In solid Sodium chloride or Table salt $\left(\mathrm{NaCl}\right)$, the molecules are tightly packed to form an ordered structure. Due to the lack of mobile electrons or ions, solid Sodium chloride $\left(\mathrm{NaCl}\right)$ does not conduct electricity.

A

• Fused $\mathrm{NaCl}$ is a molten form of $\mathrm{NaCl}$. Fused $\mathrm{NaCl}$ dissociates to form Sodium ion$\left({\mathrm{Na}}^{+}\right)$ and Chloride ion$\left({\mathrm{Cl}}^{-}\right)$. Due to the presence of mobile ions, fused $\mathrm{NaCl}$ can conduct electricity.

$\mathrm{NaCl}\left(\mathrm{l}\right)\to {\mathrm{Na}}^{+}\left(\mathrm{aq}\right)+{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)$

C

• Brine solution is a concentrated aqueous solution of Sodium chloride $\left(\mathrm{NaCl}\right)$. Aqueous solution of Sodium chloride dissociates to form Sodium ion$\left({\mathrm{Na}}^{+}\right)$ and Chloride ion$\left({\mathrm{Cl}}^{-}\right)$. Due to the presence of mobile ions, Brine solution can conduct electricity.

$\mathrm{NaCl}\left(\mathrm{aq}\right)\to {\mathrm{Na}}^{+}\left(\mathrm{aq}\right)+{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)$

D

• Due to the presence of mobile electrons in metals, Copper (Cu) can conduct electricity.

Hence, option (B) is correct. Solid NaCl does not conduct electricity.