a)
\(K_x\left(OH\right)_y\\ \left\{{}\begin{matrix}x=1\\y=1\end{matrix}\right.\\ \Rightarrow CTHH:KOH\)
\(Mg_x\left(OH\right)_y\\ \Rightarrow\left\{{}\begin{matrix}x=1\\y=2\end{matrix}\right.\\ \Rightarrow CTHH:Mg\left(OH\right)_2\)
\(Fe_x\left(OH\right)_y\\\Rightarrow \left[{}\begin{matrix}\left\{{}\begin{matrix}x=1\\y=2\end{matrix}\right.\\\left\{{}\begin{matrix}x=1\\y=3\end{matrix}\right.\end{matrix}\right.\\\Rightarrow CTHH:\left\{{}\begin{matrix}Fe\left(OH\right)_2\\Fe\left(OH\right)_3\end{matrix}\right. \)
\(Al_x\left(OH\right)_y\\ \Rightarrow\left\{{}\begin{matrix}x=1\\y=3\end{matrix}\right.\\ \Rightarrow CTHH:Al\left(OH\right)_3\)
b)
\(K_x\left(PO_4\right)_y\\ \Rightarrow\left\{{}\begin{matrix}x=3\\y=1\end{matrix}\right.\\ \Rightarrow CTHH:K_3PO_4\\ Fe_x\left(PO_4\right)_y\\ \Rightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=3\\y=2\end{matrix}\right.\\\left\{{}\begin{matrix}x=1\\y=1\end{matrix}\right.\end{matrix}\right.\\ \Rightarrow CTHH:\left[{}\begin{matrix}Fe_3\left(PO_4\right)_2\\FePO_4\end{matrix}\right.\\ Mg_x\left(PO_4\right)_y\\ \Rightarrow\left\{{}\begin{matrix}x=3\\y=2\end{matrix}\right.\\\Rightarrow CTHH:Mg_3\left(PO_4\right)_2\\ Al_x\left(PO_4\right)_y\\ \Rightarrow\left\{{}\begin{matrix}x=1\\y=1\end{matrix}\right.\\ \Rightarrow CTHH:AlPO_4\)
