Answer:
Coefficient in front of the 
 in the balanced equation - 4
Explanation:
The unbalanced reaction is shown below as:-
On the left hand side,  
There are 1 nitrogen atom and 3 hydrogen atoms and 3 oxygen atoms
On the right hand side,  
There are 1 nitrogen atom and 2 hydrogen atoms and 2 oxygen atoms
Thus,  
Right side, 
 must be multiplied by 6 and 
 by 4 
Left side, 
 is multiplied by 5 and 
 by 4 so to balance the whole reaction.
Thus, the balanced reaction is:-
<u>Coefficient in front of the 
 in the balanced equation - 4</u>