Hoà tan hoàn toàn 35,1 gam hỗn hợp Al, Ag trong ax...

D

- Hướng dẫn giải

Phương pháp giải:

\(\begin{gathered}
Al - 3{\text{e}} \to \mathop {Al}\limits^{ + 3} + 3N{O_3}^ - \hfill \\
x\,\,\,\,\,\,\,\,\,\,3{\text{x}}\,\,\,\,\,\,\,\,\,\,\,\,{\text{ }}\,{\text{ 3x}} \hfill \\
Ag - 1{\text{e}} \to \mathop {Ag}\limits^ + + N{O_3}^ - \hfill \\
y\,\,\,\,\,\,\,\,\,\,y\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,y \hfill \\
\mathop N\limits^{ + 5} + 3{\text{e}} \to \mathop N\limits^{ + 2} O \hfill \\
\,\,\,\,\,\,\,\,\,\,0,6\,\,\,\,\,\,\,\,0,2 \hfill \\
\end{gathered} \)

m_Kl = 27x+108y =35,1 (1)

ĐLBT số mol e  => 3x+y=0,6(2)

=> x,y

=> m_muối = m_Kl + m_NO3(muối)

Giải chi tiết:

\(\begin{gathered}
Al - 3{\text{e}} \to \mathop {Al}\limits^{ + 3} + 3N{O_3}^ - \hfill \\
x\,\,\,\,\,\,\,\,\,\,3{\text{x}}\,\,\,\,\,\,\,\,\,\,\,\,{\text{ }}\,{\text{ 3x}} \hfill \\
Ag - 1{\text{e}} \to \mathop {Ag}\limits^ + + N{O_3}^ - \hfill \\
y\,\,\,\,\,\,\,\,\,\,y\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,y \hfill \\
\mathop N\limits^{ + 5} + 3{\text{e}} \to \mathop N\limits^{ + 2} O \hfill \\
\,\,\,\,\,\,\,\,\,\,0,6\,\,\,\,\,\,\,\,0,2 \hfill \\ 
\end{gathered} \)

m_Kl = 27x+108y =35,1 (1)

ĐLBT số mol e  => 3x+y=0,6(2)

=> x= 0,1, y=0,3

=> m_muối = m_Kl + m_NO3(muối)  = 35,1+  62.(3.0,1+0,3)=72,3 gam

Đáp án D