Em tham khảo nha:

\(\begin{array}{l}
a)\\
CTHH:{C_x}{H_y}{O_z}\\
x:y:z = \dfrac{{54,5}}{{12}}:\dfrac{{9,1}}{1}:\dfrac{{36,4}}{{16}} = 4,54:9,1:2,275\\
 \Rightarrow x:y:z = 2:4:1 \Rightarrow CTDGN:{C_2}{H_4}O\\
{n_R} = \dfrac{{0,224}}{{22,4}} = 0,01\,mol\\
{M_R} = \dfrac{{0,88}}{{0,01}} = 88g/mol\\
CTPT\,R:{({C_2}{H_4}O)_n}\\
 \Rightarrow 44n = 88 \Rightarrow n = 2 \Rightarrow CTPT:{C_4}{H_8}{O_2}\\
b)\\
{M_M} = \dfrac{{1,25}}{{\dfrac{1}{{22,4}}}} = 28g/mol\\
CTPT:{C_x}{H_y}\\
x:y = \dfrac{{85,71}}{{12}}:\dfrac{{14,29}}{1} = 1:2\\
 \Rightarrow CTDGN:C{H_2}\\
CTPT\,M:{(C{H_2})_n}\\
 \Rightarrow 14n = 28 \Rightarrow n = 2 \Rightarrow CTPT:{C_2}{H_4}
\end{array}\)