Gọi \(\left\{{}\begin{matrix}n_{Zn}=a\left(mol\right)\\n_{Fe}=b\left(mol\right)\\n_{Al}=c\left(mol\right)\end{matrix}\right.\) => 65a + 56b + 27c = 10,65 (1)

PTHH: Zn + 2HCl --> ZnCl₂ + H₂

            Fe + 2HCl --> FeCl₂ + H₂

            2Al + 6HCl --> 2AlCl₃ + 3H₂

=> \(n_{H_2}=a+b+1,5c=\dfrac{5,04}{22,4}=0,225\left(mol\right)\) (2)

PTHH: Zn + Cl₂ --t^o--> ZnCl₂

            2Fe + 3Cl₂ --t^o--> 2FeCl₃

            2Al + 3Cl₂ --t^o--> 2AlCl₃

=> \(n_{Cl_2}=a+1,5b+1,5c=\dfrac{5,6}{22,4}=0,25\left(mol\right)\) (3)

(1)(2)(3) => \(\left\{{}\begin{matrix}a=0,1\left(mol\right)\\b=0,05\left(mol\right)\\c=0,05\left(mol\right)\end{matrix}\right.\) => \(\left\{{}\begin{matrix}m_{Zn}=0,1.65=6,5\left(g\right)\\m_{Fe}=0,05.56=2,8\left(g\right)\\m_{Al}=0,05.27=1,35\left(g\right)\end{matrix}\right.\)

a) \(\left\{{}\begin{matrix}\%m_{Zn}=\dfrac{6,5}{10,65}.100\%=61,033\%\\\%m_{Fe}=\dfrac{2,8}{10,65}.100\%=26,291\%\\\%m_{Al}=\dfrac{1,35}{10,65}.100\%=12,676\%\end{matrix}\right.\)

b) n_HCl = 2a + 2b + 3c = 0,45 (mol)

=> m_HCl = 0,45.36,5 = 16,425 (g)

=> \(a\%=C\%=\dfrac{16,425}{200}.100\%=8,2125\%\)

c) m_{dd sau pư} = 10,65 + 200 - 0,225.2 = 210,2 (g)

=> \(\left\{{}\begin{matrix}C\%_{ZnCl_2}=\dfrac{0,1.136}{210,2}.100\%=6,47\%\\C\%_{FeCl_2}=\dfrac{0,05.127}{210,2}.100\%=3,02\%\\C\%_{AlCl_3}=\dfrac{0,05.133,5}{210,2}.100\%=3,176\%\end{matrix}\right.\)

\(n_{Cl_2}=\dfrac{13.44}{22.4}=0.6\left(mol\right)\)

\(n_{H_2}=\dfrac{11.2}{22.4}=0.5\left(mol\right)\)

\(n_{Fe}=a\left(mol\right),n_{Al}=b\left(mol\right)\)

\(n_{H_2}=a+1.5b=0.5\left(mol\right)\)

\(n_{Cl_2}=1.5a+1.5b=0.6\left(mol\right)\)

\(\Rightarrow a=b=0.2\)

\(m_X=0.2\cdot\left(56+27\right)=16.6\left(g\right)\)

Sửa: $V_{H_2}=7,168(l)$

$a\bigg)$

Đặt $n_{Mg}=x;n_{Fe}=y;n_{Al}=z$

$\to 24x+56y+27z=9,52(1)$

$n_{H_2}=\dfrac{7,168}{22,4}=0,32(mol)$

$n_{Cl_2}=\dfrac{8,064}{22,4}=0,36(mol)$

BTe: $x+y+1,5z=n_{H_2}=0,32(2)$

BTe: $x+1,5y+1,5z=n_{Cl_2}=0,36(3)$

Từ $(1)(2)(3)\to x=0,12(mol);y=0,08(mol);z=0,08(mol)$

$\to \begin{cases} \%m_{Mg}=\dfrac{0,12.24}{9,52}.100\%=30,25\%\\ \%m_{Fe}=\dfrac{0,08.56}{9,52}.100\%=47,06\%\\ \%m_{Al}=100-47,06-30,25=22,69\% \end{cases}$

$b\bigg)$

Bảo toàn H: $n_{HCl}=2n_{H_2}=0,64(mol)$

$\to C_{M_{HCl}}=\dfrac{0,64}{0,2}=3,2M$

$\to a=3,2$

$c\bigg)$

Dung dịch sau gồm $MgCl_2,FeCl_2,AlCl_3$

Bảo toàn $Mg,Al,Fe:n_{MgCl_2}=0,12(mol);n_{AlCl_3}=n_{FeCl_2}=0,08(mol)$

$\to C_{M_{MgCl_2}}=\dfrac{0,12}{0,2}=0,6M$

$\to C_{M_{AlCl_3}}=C_{M_{FeCl_2}}=\dfrac{0,08}{0,2}=0,4M$

$a\bigg)$

Đặt $n_{Mg}=x;n_{Fe}=y;n_{Al}=z$

$\to 24x+56y+27z=9,52(1)$

$n_{H_2}=\dfrac{14,336}{22,4}=0,64(mol)$

$n_{Cl_2}=\dfrac{8,064}{22,4}=0,36(mol)$

BTe: $x+y+1,5z=n_{H_2}=0,64(2)$

BTe: $x+1,5y+1,5z=n_{Cl_2}=0,36(3)$

Từ $(1)(2)(3)\to$ nghiệm âm, xem lại đề

giúp em vs

Gọi số mol Mg, Fe, Al là a, b, c

=> 24a + 56b + 27c = 23,8

PTHH: Mg + 2HCl --> MgCl₂ + H₂ 

            a------------------------->a

            Fe + 2HCl --> FeCl₂ + H₂

            b------------------------->b

            2Al + 6HCl --> 2AlCl₃ + 3H₂ 

            c------------------------->1,5c

=> a + b + 1,5c = \(\dfrac{17,92}{22,4}=0,8\left(mol\right)\)

PTHH: Mg + Cl₂ --t^o--> MgCl₂

             a-->a

            2Fe + 3Cl₂ --t^o--> 2FeCl₃

             b--->1,5b

             2Al + 3Cl₂ --t^o--> 2AlCl₃

             c--->1,5c

=> \(a+1,5b+1,5c=\dfrac{20,16}{22,4}=0,9\left(mol\right)\)

=> a = 0,3; b = 0,2; c = 0,2

=> \(\left\{{}\begin{matrix}m_{Mg}=0,3.24=7,2\left(g\right)\\m_{Fe}=0,2.56=11,2\left(g\right)\\m_{Al}=0,2.27=5,4\left(g\right)\end{matrix}\right.\)

Đáp án D

Xét trường hợp 20,4 gam A tác dụng với dung dịch HCl dư:

Gọi số mol các chất là Al: a mol; Zn: b mol; Fe: c mol

Ta có:

Các quá trình nhường, nhận electron:

Xét trường hợp 0,2 mol A tác dụng với Cl₂:

Gọi số mol các chất là Al: ka mol; Zn: kb mol; Fe: kc mol

Ta có: 

Các quá trình nhường, nhận electron:

Lấy (IV) chia (III) vế với vế ta được:

Trong \(20,4g\) hỗn hợp có: \(\left\{{}\begin{matrix}n_{Zn}=a\left(mol\right)\\n_{Fe}=b\left(mol\right)\\n_{Al}=c\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow65a+56b+27c=20,4\left(1\right)\)

\(n_{H_2}=\dfrac{10,08}{22,4}=0,45mol\)

\(BTe:2n_{Zn}+2n_{Fe}+3n_{Al}=2n_{H_2}\)

\(\Rightarrow2a+2b+3c=2\cdot0,45\left(2\right)\)

Trong \(0,2mol\) hhX có \(\left\{{}\begin{matrix}Zn:ka\left(mol\right)\\Fe:kb\left(mol\right)\\Al:kc\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow ka+kb+kc=0,2\)

\(n_{Cl_2}=\dfrac{6,16}{22,4}=0,275mol\)

\(BTe:2n_{Zn}+3n_{Fe}+3n_{Al}=2n_{Cl_2}\)

\(\Rightarrow2ka+3kb+3kc=2\cdot0,275\)

Xét thương:

 \(\dfrac{ka+kb+kc}{2ka+3kb+3kc}=\dfrac{0,2}{2\cdot0,275}\Rightarrow\dfrac{a+b+c}{2a+3b+3c}=\dfrac{4}{11}\)

\(\Rightarrow3a-b-c=0\left(3\right)\)

Từ (1), (2), (3)\(\Rightarrow\left\{{}\begin{matrix}a=0,1mol\\b=0,2mol\\c=0,1mol\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}m_{Zn}=6,5g\\m_{Fe}=11,2g\\m_{Al}=2,7g\end{matrix}\right.\)