In NH4OH, the compounds that make it up are NH4+ and OH- Therefore N exists in the ammonium form. In the ammonium ion 4H atoms are connected to N. N is more electronegative than H, therefore when H bonds to N, H is the more positive atom therefore each H has a charge of +1, since there are 4 H atoms the charge contributed by the 4H atoms are +1 * 4 = +4 the overall charge of NH4 is +1 Charge of N (+) +4 = +1 Charge of N = +1 - 4 Therefore oxidation state of N in NH4 is = -3