Đáp án:
\[n_{CO_2}=\dfrac{4,4}{44}=0,1(mol)\]
\[\to n_C=0,1(mol)\]
\[n_{H_2O}=\dfrac{0,9}{18}=0,05(mol)\]
\[\to n_H=0,05\times 2=0,1(mol)\]
Vì $m_C+m_H=12.0,1+0,1=1,3=m_A$
$\to A$ chứa C, H
$\to$ A có dạng $C_xH_y$
$\to x:y=0,1:0,1=1:1$
$\to CTTQ: {(CH)}_n$
$\to M_{{(CH)}_n}=26(g/mol)$
$\to 13n=26$
$\to n=2$
$\to C_2H_2$