a, \(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\)
PT: \(Mg+2CH_3COOH\rightarrow\left(CH_3COO\right)_2Mg+H_2\)
Theo PT: \(n_{CH_3COOH}=2n_{Mg}=0,4\left(mol\right)\)
\(\Rightarrow C_{M_{CH_3COOH}}=\dfrac{0,4}{0,2}=2\left(M\right)\)
b, \(n_{\left(CH_3COO\right)_2Mg}=n_{Mg}=0,2\left(mol\right)\)
\(\Rightarrow m_{\left(CH_3COO\right)_2Mg}=0,2.142=28,4\left(g\right)\)