Đặt \(A< R< B\)
\(PTHH:2R+2xH_2O\rightarrow2R\left(OH\right)_x+xH_2\)
\(n_{H_2}=\frac{3,36}{22,4}=0,15\left(mol\right)\)
\(\rightarrow n_R=\frac{0,3}{x}\left(mol\right)\)
\(\rightarrow M_R=\frac{8,5}{\frac{0,3}{x}}=28,\left(3\right)x\)
\(BL:\\ x=1\rightarrow A< 28,3< B\\ \Rightarrow\left\{{}\begin{matrix}A:Na\left(Natri\right)\\B:K\left(Kali\right)\end{matrix}\right.\)