\(R + 2HCl ---> RCl_2 + H_2\)
\(n_{H_2}= \dfrac{4,48}{22,4}= 0,2 mol\)
\(Theo PTHH: n_R = n_{H_2} = 0,2 mol\)
\(\Rightarrow M_R= \dfrac{13}{0,2} = 65 ( Zn)\)
\(b)\)
\(n_{HCl}=2n_{H_2}= 0,4 mol\)\(\Rightarrow m_{HCl} = 14,6g\)
\(m_{dd HCl} =\dfrac{14,6 . 100}{20}= 73g\)
\(BTKL:\)
\(m_{dd ZnCl_2}= m_{Zn} + m_{dd HCl} - m_{H_2}\)
\(= 13 + 73 - 0,2 . 2\)
\(= 85,6 g\)
\(Theo PTHH:\)
\(m_{ZnCl_2}= 0,2 . 136= 27,2g\)
C%= \(\dfrac{27,2}{85,6} . 100 \) ~ 31,78 %