Which of the following is a non-conductor of electricity?

Reduction of water is carried out near the cathode in the presence of aqueous $Na^{+}$ ions. Explain why.

The use of electrolysis is:

During the electrolysis of higher concentration of $H_2SO_4$,the product obtained at anode is . . . . . . .

Predict the products of electrolysis in each of the following:
$(i)$ An aqueous solution of $AgNO_3$ with silver electrodes.
$(ii)$ An aqueous solution of $AgNO_3$ with platinum electrodes.
$(iii)$ $A$ dilute solution of $H_2SO_4$ with platinum electrodes.
$(iv)$ An aqueous solution of $CuCl_2$ with platinum electrodes.

Which of the following conducts electricity?