Balance each of the following equations according to the half-reaction method:
(a) zn(s) + no3 −(aq) ⟶ zn2+(aq) + n2 (g) (in acid)
(b) zn(s) + no3 −(aq) ⟶ zn2+(aq) + nh3 (aq) (in base)
(c) cus(s) + no3 −(aq) ⟶ cu2+(aq) + s(s) + no(g) (in acid)
(d) nh3 (aq) + o2 (g) ⟶ no2 (g) (gas phase)
(e) h2 o2 (aq) + mno4 −(aq) ⟶ mn2+(aq) + o2 (g) (in acid)
(f) no2 (g) ⟶ no3 −(aq) + no2 −(aq) (in base)
(g) fe 3+(aq) + i −(aq) ⟶ fe 2+(aq) + i2 (aq)