In the redox reaction
`xMnO+yPbO_(2)+zHNO_(3) rarr HMnO_(4)+Pb(NO_(3))_(2)+H_(2)O`

PbO_(2) ↓+HNO_(3)("Conc.") to Pb(NO_(3))_(2)+H_(2)O+[O]

PbO_(2)+HNO_(3)("Conc.") to Pb(NO_(3))_(2)+H_(2)O+[O]

For the redox reaction xP_(4)+yHNO_(3)rarrH_(3)PO_(4)+NO_(2)+H_(2)O

PbO_(2)↓+HNO_(3)("Conc.") to Pb(NO_(3))_(2)+H_(2)O+[O]

In the redox reaction xKMnO_(4)+NH_(3)toyKNO_(3)+ MnO_(2)+KOH+H_(2)O

In the redox reaction : xKMnO_(4) to +yNH_(3) to KNO_(3)+MnO_(2)+KOH+H_(2)O

Suggest a scheme of classification of the following redox reactions (a) N_(2) (g) + O_(2) (g) rarr 2 NO (g) (b) 2 Pb (NO_(3))_(2) (s) rarr 2 PbO (s) + 4 NO_(2) (g) + O_(2) (g) (c) NaH(s) + H_(2) O (l) rarr NaOH (aq) + H_(2) (g) (d) 2NO_(2) (g) + 2OH^(-) (aq) rarr NO_(2)^(-) (aq) + NO_(3)^(-) (aq) + H_(2) O (l)

The ratio of coefficient of HNO_(3), Fe(NO_(3))_(2) and NH_(4)NO_(3) in the following redox reaction Fe + HNO_(3) rarr Fe (NO_(3))_(2) + NH_(4)NO_(3) + H_(2)O are respectively