Question

Which of the following can not conduct electricity in a fused or molten state?

• A. $NaCl$
• B. $ZnS$
• C. $CsCl$
• D. $BeC{l}_2$

Answer 1

The correct option is D $BeC{l}_2$

In solid state, the ionic crystals act as insulator but in fused state, ionic compounds have free cations and anions which can move easily to conduct electricity. $NaCl,ZnS,CsCl$ are ionic in nature. So, they can conduct electricity.

However, $BeC{l}_2$ has a covalent character due to small size of berylium. In fused state, $BeC{l}_2$ exists in polymeric state. So, it does not have free ions to conduct electricity. Thus, they act as covalent crystals and are poor conductor of electricity.