\(P_1:2K+2H_2O\rightarrow2KOH+H_2\left(1\right)\\ P_2:Fe+2HCl\rightarrow FeCl_2+H_2\left(2\right)\\ 2K+2HCl\rightarrow2KCl+H_2\left(3\right)\)
\(n_{H_2\left(1\right)}=\dfrac{V}{22,4}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\\ n_{HCl}=\dfrac{m}{M}=\dfrac{32,85}{36,5}=0,9\left(mol\right)\)
Theo \(pthh\left(1\right)n_K=2n_{H_2}=2\cdot0,15=0,3\left(mol\right)\)
Theo \(pthh\left(3\right)n_{HCl\left(3\right)}=n_K=0,3\left(mol\right)\)
\(\Rightarrow n_{HCl\left(2\right)}=n_{HCl}-n_{HCl\left(3\right)}=0,9-0,3=0,6\left(mol\right)\)
Theo \(pthh\left(2\right)n_{Fe}=\dfrac{1}{2}n_{HCl\left(2\right)}=\dfrac{1}{2}\cdot0,6=0,3\left(mol\right)\)
\(\Rightarrow m_K=2\cdot n\cdot M=2\cdot0,3\cdot39=23,4\left(g\right)\\ m_{Fe}=n\cdot M=2\cdot0,3\cdot56=33,6\left(g\right)\\ \)
\(\Rightarrow m_{h^2\text{ }X}=m_K+m_{Fe}=23,4+33,6=57\left(g\right)\)
