Giúp với ạ xhjxhdhjhxhd

$\begin{array}{l} a)\\ 2CH_3COOH+Mg\to (CH_3COO)_2Mg+H_2\\ n_{Mg}=\dfrac{7,2}{24}=0,3(mol)\\ n_{H_2}=n_{Mg}=0,3(mol)\\ V_{H_2}=0,3.22,4=6,72(l)\\ n_{CH_3COOH}=2n_{H_2}=0,6(mol)\\ m_{CH_3COOH}=0,6.60=36(g)\\ b)\\ CH_3COOH+C_2H_5OH \buildrel{{H_2SO_4(dac)\ , t^o }}\over\rightleftharpoons  CH_3COOC_2H_5+H_2O\\ n_{CH_3COOC_2H_5}=n_{CH_3COOH}=0,6(mol)\\ m_{CH_3COOC_2H_5}=0,6.88.85\%=44,88(g) \end{array}$