Answer:
Option A. 
2Na + 2H2O —> 2NaOH + H2 
Explanation:
To know which option is correct, we shall do a head count of the number of atoms present on both side to see which of them is balanced. This is illustrated below below:
For Option A:
2Na + 2H2O —> 2NaOH + H2
Reactant >>>>>>> Product
2 Na >>>>>>>>>>> 2 Na
4 H >>>>>>>>>>>> 4 H
2 O >>>>>>>>>>>> 2 O
Thus, the above equation is balanced. 
For Option B:
2Na + 2H2O —> NaOH + H2
Reactant >>>>>>> Product
2 Na >>>>>>>>>>> 1 Na
4 H >>>>>>>>>>>> 3 H
2 O >>>>>>>>>>>> 1 O
Thus, the above equation is not balanced.
For Option C:
2Na + H2O —> 2NaOH + H2
Reactant >>>>>>> Product
2 Na >>>>>>>>>>> 2 Na
2 H >>>>>>>>>>>> 4 H
1 O >>>>>>>>>>>> 2 O
Thus, the above equation is not balanced. 
For Option D:
Na + 2H2O —> NaOH + 2H2
Reactant >>>>>>> Product
1 Na >>>>>>>>>>> 1 Na
4 H >>>>>>>>>>>> 5 H
2 O >>>>>>>>>>>> 1 O
Thus, the above equation is not balanced. 
From the illustrations made above, only option A is balanced.
 
        
             
        
        
        
Answer:
Ferric oxide reacts with aluminium to produce aluminium oxide and iron. The balanced chemical equation for the given reaction is : Fe2O3 + 2Al → Al2O3 + 2Fe.
 
        
             
        
        
        
All compounds are molecules because a molecule is 2 or more substances/elements combined and a compound is 2 or more elements combined. But not all molecules are elements because some molecules are just combined substances with no elements combined at all.