How many of the following metals can be obtained by electrolysis of aqueous solutions of their salts ?
Ag, Ca, Cu, Mg, Na, Al.

Answer

2

Explanation

Ca,Mg. NaandAl have lower reduction potential than water (`E^(0) = -0.83V`). hence, they cannot be reduced in their aqueous solution. Instead water will get reduced to liberate `H_(2)`.