Question

Which of the following properly lists the metals in order from decreasing to increasing ease of oxidation?

A. K < Cr < Cu < Ag
B. Ag < Cr < Cu < K
C. K < Cu < Cr < Ag
D. Ag < Cu < Cr < K

Answer 1

I know it is either B or D, since I know that K will oxidize in water, and Ag will have a tougher time oxidizing. I am going to lean towards D for my answer.

Answer 2

Answer is: D. Ag < Cu < Cr < K.

Reactivity series is an empirical progression of a series of metals, arranged by their reactivity from highest to lowest (alkaline metals have highest reactivity and Noble metals lowest reactivity):

K > Ba > Sr > Na > Ca > Mg > Be > Al > Mn > Zn > Cr> Fe > Cd > Co > Ni > Sn > Pb > H(in acids) > Cu > Hg > Ag.

Metal higher in the reactivity series will displace another and it will be oxidized.

For example, potassium is more reactive than silver.

Chemical reaction: K + AgCl → KCl + Ag.

Potassium is oxidized (from oxidation number 0 to +1) and silver is reduced (from oxidation number +1 to 0).