dA/O2=\(\dfrac{M_A}{32}\)=0,5 => MA=16g/mol
mC=\(\dfrac{75}{100}.16\)=12g =>nC=\(\dfrac{12}{12}\)=1 mol
mH=16-12=4g/mol =>nO=\(\dfrac{4}{1}\)=4 mol
CTHH của A là CH4
Ta có dA/O2=0,5=>\(\dfrac{M_A}{M_{o_2}}\)=0,5=>MA=0,5.32=16
mC=\(\dfrac{16.75}{100}\)=12(g)
mH=\(\dfrac{16.25}{100}\)=4(g)
nC=\(\dfrac{12}{12}\)=1(mol)
nH=\(\dfrac{4}{1}\)=4(mol)
=>CTHH là CH4