explain why anhydrous HCl is a poor conductor while aqueous hcl is an excellent conductor
Anhydrous HCl does not contain any free ions. In the absence of free ions no conductivity of electricity could take place. But when HCl is dissolved in water, it dissociates into hydronium ion(H3O+) and chloride ion(Cl-). Due to presence of free ions, Electricity can be conducted in an aquous solution of HCl.