Q.

Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because                 [2016]

1 zinc is lighter than iron  
2 zinc has lower melting point than iron  
3 zinc has lower negative electrode potential than iron  
4 zinc has higher negative electrode potential than iron.  

Ans.

(4)

Reduction potential values of EZn2+/Zn=-0.76 V and EFe2+/Fe=-0.44 V

Thus, due to higher negative electrode potential value of zinc than iron, iron cannot be coated on zinc.