(1)
2NaHCO3=Na2CO3+CO2+H2O----------n(CO2)=n(H2O)=b/2 mol
2Na2O2+2CO2=2Na2CO3+O2------------n(O2)=b/4 mol
2Na2O2+2H2O=4NaOH+O2---------------2xmolH2O-----------xmolO2
b/4 + x =b/2 -2x-------------------x=b/12 mol
a/b=(b/2+b/6)/b==2:3
(2)
a=0----- b>0-------(CO2,H2O)-------M=31
a/b =1-------------(O2)------------M=32
a/b=1/2------------(O2,2H2O)-------M=68/3