Solution:

Activity Series of Metals in Aqueous Solution
Metal	Oxidation Reaction
Lithium	Li(s)	→	Li+(aq) + e-	r .	Ease of oxidation increases
Potassium	K(s)	→	K+(aq) + e-
Barium	Ba(s)	→	Ba2+(aq) + 2e-
Calcium	Ca(s)	→	Ca2+(aq) + 2e-
Sodium	Na(s)	→	Na+(aq) + e-
Magnesium	Mg(s)	→	Mg2+(aq) + 2e-
Aluminum	Al(s)	→	Al3+(aq) + 3e-
Manganese	Mn(s)	→	Mn2+(aq) + 2e-
Zinc	Zn(s)	→	Zn2+(aq) + 2e-
Chromium	Cr(s)	→	Cr3+(aq) + 3e-
Iron	Fe(s)	→	Fe2+(aq) + 2e-
Cobalt	Co(s)	→	Co2+(aq) + 2e-
Nickel	Ni(s)	→	Ni2+(aq) + 2e-
Tin	Sn(s)	→	Sn2+(aq) + 2e-
Lead	Pb(s)	→	Pb2+(aq) + 2e-
Hydrogen	H2(g)	→	2H+(aq) + 2e-
Copper	Cu(s)	→	Cu2+(aq) + 2e-
Silver	Ag(s)	→	Ag+(aq) + e-
Mercury	Hg(l)	→	Hg2+(aq) + 2e-
Platinum	Pt(s)	→	Pt2+(aq) + 2e-
Gold	Au(s)	→	Au3+(aq) + 3e-

Based on their relative positions in table, which ion will have a more positive standard reduction potential?