PTHH: A2O + H2O → 2AOH
\(n_{AOH}\) = 0,2 ×1=0,2 ( mol ) ( vì 200 ml = 0,2 l )
Theo PT: \(n_{A_2O}=\dfrac{1}{2}n_{AOH}=\) = 12 × 0,2 = 0,1 ( mol )
⇒ \(M_{A_2O}=\dfrac{9,4}{0,1}=94\) ( G )
Ta có: 2\(M_A\) + 16 = 94
⇔ 2\(M_A\)= 78
⇔ \(M_A\) =39 ( g )
Vậy A là kim loại Kali K
\(n_{MOH}=0.2\cdot1=0.2\left(mol\right)\)
\(M_2O+H_2O\rightarrow2MOH\)
\(0.1........................0.2\)
\(M_{M_2O}=\dfrac{9.4}{0.1}=94\)
\(\Rightarrow M=\dfrac{94-16}{2}=39\)
\(CT:K_2O\)