# Which of the oxide groups among the following

Question:

Which of the oxide groups among the following cannot be reduced by carbon :-

1. $\mathrm{Fe}_{2} \mathrm{O}_{3}, \mathrm{ZnO}$

2. $\mathrm{PbO}, \mathrm{Fe}_{2} \mathrm{O}_{4}$

3. $\mathrm{Cu}_{2} \mathrm{O}, \mathrm{SnO}_{2}$

4. $\mathrm{CaO}, \mathrm{K}_{2} \mathrm{O}$

Correct Option: , 4

Solution:

More reactive metal such as K and "Ca" etc. can be used by electrolytic reduction method but

not by  carbon reduction method.