Strong acids and strong bases are almost completely ionized in aqueous solutions. Therefore, their solutions contain large number of ions and hence, they behave as strong electrolytes. They are very good conductors of electricity. On the other hand weak acids and weak bases are weakly ionized in aqueous solution. Therefore, they produce less ions in the solution and hence behave as weak electrolytes and are poor conductors of electricity.
The solutions of strong acids such as HCl, H2SO4 and HNO3, and strong bases such as NaOH and KOH behave as good conductors.
On the other hand, aqueous solutions of weak acids such as CHFOOH and H2PO4, and weak bases such as Ca(OH)2, Mg(OH)2 and NH3 behave as poor conductors of electricity.
The aqueous solutions of non-electrolytes such as glucose, sucrose and ethanol are bad conductors of electricity.