Answer to Question #264029 in Inorganic Chemistry for queen

Question

1.      What is the oxidation state of the underlined element in (a) P₄, (b) Al₂O₃, (c) MnO₄ ^-, (d) NaH, (e) H₂O₂; (f) Fe₃O₄?

Answer 1

a) $P_4$ phosphorus bound to the same atom so oxidation number is zero.

b) $Al_2O_3 (2Al+3\times -2=0)$, so oxidation number of Al is +3

c) $MnO_4^- ( Mn +4\times -2=-1),$ oxidation number of Mn=+7

d) $NaH ( 1+H=0)$, oxidation number of H=-1 and that of Na=+1

e) $H_2O_2(2\times (+1)+2O=0)$, oxidation of oxygen =-1

f) $Fe_3O_4(2Fe+3\times -2=0)$, so oxidation number of Fe=+3

Also for FeO, Fe+-2=0, therefore oxidation of Fe =+2

Thus oxidation of Fe= +3 and +2