a,
\(n_C=n_{CO2}=0,2\left(mol\right)\Rightarrow m_C=2,4\left(g\right)\)
\(n_H=2n_{H2O}=0,6\left(mol\right)\Rightarrow m_H=0,6\left(g\right)\)
\(\Rightarrow m_O=4,6-2,4-0,6=1,6\left(g\right)\)
X gồm C, H, O.
b,
\(n_O=0,1\left(mol\right)\)
\(n_C:n_H:n_O=2:6:1\)
Nên CTĐGN (C2H6O)n
\(M_X=1,43745.32=46\)
\(\Rightarrow n=1\)
Vậy CTPT X là C2H6O