Question

The most active metal among the following is:

• A. Fe
• B. Zn
• C. Ni
• D. Cu

Hint:

Most active \(=\) most negative reduction potential \(=\) highest in the activity series. Compare Zn, Fe, Ni, Cu.

Answer 1

The Correct Option is B

Step 1: What 'most active' means. The most active (most reactive) metal is the strongest reducing agent, i.e. the one that loses electrons most easily. This is the metal with the most negative standard reduction potential and the highest position in the activity/electrochemical series.
Step 2: Compare standard reduction potentials.
\(Zn^{2+}/Zn = -0.76\,V\)
\(Fe^{2+}/Fe = -0.44\,V\)
\(Ni^{2+}/Ni = -0.25\,V\)
\(Cu^{2+}/Cu = +0.34\,V\)
Step 3: Rank. The most negative value belongs to zinc, so Zn is oxidised most readily and is the most active metal.
Step 4: Others. Cu is the least active (positive potential, a noble-ish metal); Fe and Ni lie in between.
\[\boxed{\text{Zn (option ii)}}\]