A correct electrochemical series can be obtained from K, Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging?

A.

Al and Mg

B.

Zn and Fe

C.

Zn and Pb

D.

Pb and H

E.

Au and Hg

Correct answer is A

The electrochemical series, also known as the activity series, is a list of metals listed in order of decreasing reactivity or in order of decreasing ease of oxidation. 

Magnesium comes before Aluminium in the series