Explanation:
In NH4OH, there are 5 hydrogen atoms having oxidation state +1( H can also have -1 oxidation state when it is bonded to more electropositive atom than H)
NH4OH contains one Oxygen atom having -2 oxidation state .
And also NH4OH have zero net charge
Let N has 'x' oxidation state
Hence,
x+5(+1)+(-2)=0
x+3=0
x= -3
Thus, Nitrogen have -3 oxidation state.
