E chỉ biết làm câu a thôi
\(n_{H_2}=\frac{3,36}{22,4}=0,15\left(mol\right);n_{O_2}=\frac{1,12}{22,4}=0,05\left(mol\right)\)
\(M_{A\left(trungbinh\right)}=\frac{0,15.2+0,05.32}{0,15+0,05}=9,5\left(\frac{g}{mol}\right)\)
\(d_{\frac{A}{H_2}}=\frac{M_A}{M_{H_2}}=\frac{9,5}{2}=4,75\left(lần\right)\)