Solid NaCl is a bad conductor of electricity because:
A. In solid NaCl, there are no ions
B. In solid NaCl, ions cannot move freely
C. In solid NaCl, there are no electrons
D. None of the above

B. In solid NaCl, ions cannot move freely

Solid NaCl consists of a three-dimensional lattice of alternating sodium (Na+) and chloride (Cl-) ions held together by strong electrostatic forces. In this solid state, the ions are fixed in their positions and cannot move freely. Since electrical conductivity in a material typically requires the movement of charged particles (usually ions or electrons), the inability of ions to move in the solid lattice of NaCl makes it a poor conductor of electricity.