The balanced chemical reaction is :
[tex]O_2 + 4Na \ -> \ 2Na_2O[/tex]
Number of moles of Na, [tex]n = \dfrac{14.6}{23} = 0.635 \ mol[/tex] .
Now, from balance chemical reaction we can see that 1 mole of oxygen reacts with 4 moles of sodium.
So, number of moles of oxygen are :
[tex]n = \dfrac{0.635}{4}\ mole[/tex]
So, amount of oxygen required is :
[tex]m = \dfrac{0.635 \times 32}{4}\ gm\\\\m = 5.08 \ gm[/tex]
Therefore, 5.08 gram of oxygen will react with 14.6 gram of sodium.
