`a)PTHH:`
`Fe + 2HCl -> FeCl_2 + H_2`
`0,05` `0,1` `(mol)`
`n_[Fe]=[2,8]/56=0,05(mol)`
`b)m_[dd HCl]=50.1,18=59(g)`
`=>C%_[HCl]=[0,1.36,5]/59 . 100~~6,19%`
\(a.Fe+2HCl\rightarrow FeCl_2+H_2\\ b.n_{Fe}=\dfrac{2,8}{56}=0,05\left(mol\right)\\ n_{HCl}=2n_{Fe}=0,1\left(mol\right)\\ m_{ddHCl}=50.1,18=59\left(g\right)\\ C\%_{HCl}=\dfrac{0,1.36,5}{59}.100=6,19\%\)