Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because

Solution & Explanation

\textbf{Answer:} (D) Zinc has higher (more) negative electrode potential than iron. \textbf{Solution:} Compare the standard reduction potentials: $E_{\mathrm{Zn}{}^{2+}/\mathrm{Zn}}^{\circ }=-0.76\text{V}$ and $E_{\mathrm{Fe}{}^{2+}/\mathrm{Fe}}^{\circ }=-0.44\text{V}$. Since $-0.76\text{V}$ is more negative than $-0.44\text{V}$, zinc is oxidised more easily than iron. $\mathrm{Zn}\to \mathrm{Zn}{}^{2+}+2\mathrm{e}{}^{-}$ Zinc therefore acts as the anode and is preferentially corroded, protecting the iron beneath (sacrificial / cathodic protection). The reverse (coating iron on zinc) would leave zinc unprotected, so it is not done.