Complete the chemical formula of the following compounds:
a) NH4OH: Ammonium hydroxide
b) Na2SO3: Sodium sulfite
c) Rhodium (III) oxide: Rh2O3
d) BF3: Boron trifluoride
e) Hydrosulfuric acid: H2S
f) Sulfurous acid: H2SO3
g) HCN (aq): Hydrocyanic acid
h) MnO2: Manganese dioxide