Question

X and Y are two metals. When burnt in air, X forms only oxide while Y forms oxide and nitride. The metals X and Y may be :

• A. $Ca$ and $Mg$
• B. $Na$ and $Mg$
• C. $Li$ and $Na$
• D. $Na$ and $K$

Answer 1

The correct option is B $Na$ and $Mg$

Reaction with air;
$Mg+air\to MgO+M{g}_3{N}_2$
and,
sodium forms peroxide and monoxide as product with air
$Na+air\to N{a}_2{O}_2+N{a}_{2}O$.