Cân bằng các phương trình phản ứng oxi hóa – khử sau bằng phương pháp thăng bằng electron:
a) KMnO4 + HCl → KCl + MnCl2 + Cl2 + H2O.
b) HNO3 + HCl → NO2 + Cl2 + H2O.
c) HClO3 + HCl → Cl2 + H2O.
d) PbO2 + HCl → PbCl2 + Cl2 + H2O.
Câu a:
\(\begin{array}{l}
16H\mathop {Cl}\limits^{ - 1} + 2K\mathop {Mn}\limits^{ + 7} {O_4} \to 2KCl + 2\mathop {Mn}\limits^{ + 2} C{l_2} + 5\mathop {C{l_2}}\limits^0 + 8{H_2}O\\
\;
\end{array}\)
\(\begin{array}{*{20}{c}}
{5 \times }\\
\;\\
{2 \times }
\end{array}\left\{ {\begin{array}{*{20}{c}}
{2\mathop {Cl}\limits^{ - 1} \to \mathop {C{l_2}}\limits^0 + 2e}\\
\;\\
{\mathop {Mn}\limits^{ + 7} + 5e \to \mathop {Mn}\limits^{ + 2} }
\end{array}} \right.\)
Câu b:
\(2H\mathop {Cl}\limits^{ - 1} + 2H\mathop N\limits^{ + 5} {O_3} \to 2\mathop N\limits^{ + 4} {O_2} + C{l_2} + 2{H_2}O\)
\(\begin{array}{*{20}{c}}
{1 \times }\\
\;\\
{2 \times }
\end{array}\left\{ {\begin{array}{*{20}{c}}
{2\mathop {Cl}\limits^{ - 1} \to \mathop {C{l_2}}\limits^0 + 2e}\\
\;\\
{\mathop N\limits^{ + 5} + 1e \to \mathop N\limits^{ + 4} \;\;\;\;}
\end{array}} \right.\)
Câu c:
\(5H\mathop {Cl}\limits^{ - 1} + H\mathop {Cl}\limits^{ + 5} {O_3} \to 3\mathop {C{l_2}}\limits^0 + 3{H_2}O\)
\(\begin{array}{*{20}{c}}
{5 \times }\\
\;\\
{1 \times }
\end{array}\left\{ {\begin{array}{*{20}{c}}
{2\mathop {Cl}\limits^{ - 1} \to \mathop {C{l_2}}\limits^0 + 2e\;\;}\\
\;\\
{2\mathop {Cl}\limits^{ + 5} + 10e \to C{l_2}}
\end{array}} \right.\)
Câu d:
\(\mathop {Pb}\limits^{ + 4} {O_2} + 4H\mathop {Cl}\limits^{ - 1} \to \mathop {Pb}\limits^{ + 2} C{l_2} + \mathop {C{l_2}}\limits^0 + 2{H_2}O\)
\(\begin{array}{*{20}{c}}
{1 \times }\\
\;\\
{1 \times }
\end{array}\left\{ {\begin{array}{*{20}{c}}
{2\mathop {Cl}\limits^{ - 1} \to \mathop {C{l_2}}\limits^0 + 2e}\\
\;\\
{\mathop {Pb}\limits^{ + 4} + 2e \to \mathop {Pb}\limits^{ + 2} \;\;}
\end{array}} \right.\)
-- Mod Hóa Học 10
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