Give one word or a phrase for the statement : Electrode used as cathode in electrorefining of impure copper.

Arrange the following according to the instruction given in the bracket : Mg²⁺, Cu²⁺, Na¹⁺, H¹⁺ [In the order of preferential discharge at the cathode. ]

State one relevant reason for : Graphite anode is preferred to platinum in the electrolysis of molten lead bromide.

Name the particles present in :

(i) Strong electrolyte

(ii) Non-electrolyte

(iii) Weak electrolyte