The equation which is balanced and represents the correct product(s) is :
As we learned
Oxides and hydroxides of Li and Mg -
1. They are much less soluble
2. Their hydroxides decomposes on heating
3. Their oxides don't combine with excess oxygen to give superoxide
This reaction is unfavourable in forward direction as Li2O is more stable than K2O . In eqn 3 charge on should be -2 inspite of +2.
In eqn 4, product should be .
Only, is balanced and represents correct products.