\(a,M_A=22,4.2,679=60\left(g\text{/}mol\right)\\ n_C=n_{CO_2}=\dfrac{10,56}{44}=0,24\left(mol\right)\\ n_H=2n_{H_2O}=2.\dfrac{4,32}{18}=0,48\left(mol\right)\\ n_O=\dfrac{7,2-0,24.12-0,48}{16}=0,24\left(mol\right)\)
CTPT của A có dạng: \(C_xH_yO_z\left(x,y,z\in N\text{*}\right)\)
\(\rightarrow x:y:z=0,24:0,48:0,24=1:2:1\\ \rightarrow CTĐGN:\left(CH_2O\right)_n\left(n\in N\text{*}\right)\\ \rightarrow30n=60\\ \rightarrow n=2\left(TM\right)\)
\(CTPT:C_2H_4O_2\)
b, A là axit hữu cớ
\(\rightarrow CTCT:CH_3-COOH\)