1.
a,
N+2 -> N+4 +2e (2x)
O2 + 4e -> O-2 (1x)
=> 2NO+ O2 -> 2NO2
b,
2Fe -> 2Fe+3 +6e (1x)
S+6 +2e -> S+4 (3x)
2Fe+ 6H2SO4 -> Fe2(SO4)3+ 3SO2+ 6H2O
c,
2Fe+3 +6e -> 2Fe (1x)
C+2 -> C+4 +2e (3x)
Fe2O3+ 3CO (t*)-> 2Fe+ 3CO2
2.
a, nH2= 3,36/22,4= 0,15 mol
R+ H2O -> ROH+ 1/2H2
=> nR= 0,3 mol
=> MR= 6,9/0,3= 23. Vậy R là Na
b, nNa= nNaOH= 0,3 mol
2NaOH+ H2SO4 -> Na2SO4+ H2O
=> nH2SO4= 0,15 mol
=> V H2SO4= 0,15/0,5= 0,3l= 300ml