Cân bằng các phản ứng oxi hóa – khử, xác định chất oxi hóa, chất khử của các PTHH sau:
a. Fe + HNO3 → Fe(NO3)3 + N2 + H2O
b. Fe + HNO3 → Fe(NO3)3 + N2O + H2O
c. Fe + HNO3 → Fe(NO3)3 + NO + H2O
d. Fe + HNO3 → Fe(NO3)3 + NO2 + H2O
e. Fe + HNO3 → Fe(NO3)3 + NH4NO3 + H2O
f. Cu + H2SO4→ CuSO4 + SO2 + H2O
g. S + HNO3 → H2SO4 + NO2 + H2O
h. FeS + O2 → Fe2O3 + SO2
i. Al + O2 → Al2O3
k. NH3 + Cl2 → N2 + HCl
l. NH3 + CuO → Cu + N2 + H2O
m. MnO2 + HCl → MnCl2 + Cl2 + H2O
n. HNO3 + H2S → S + NO + H2O
Đáp án:
\(\begin{array}{l}
\begin{array}{*{20}{l}}
{5Fe}& + &{12HN{O_3}}& \to &{5Fe{{\left( {N{O_3}} \right)}_2}}& + &{6{H_2}O}& + &{{N_2}}
\end{array}\\
8Fe\; + \;30HN{O_3}\; \to \;8Fe{\left( {N{O_3}} \right)_3}\; + \;3{N_2}O\; + \;15{H_2}O\\
\begin{array}{*{20}{l}}
{Fe}& + &{4HN{O_3}}& \to &{2{H_2}O}& + &{NO}& + &{Fe{{\left( {N{O_3}} \right)}_3}}
\end{array}\\
\begin{array}{*{20}{l}}
{Fe}& + &{6HN{O_3}}& \to &{3{H_2}O}& + &{3N{O_2}}& + &{Fe{{\left( {N{O_3}} \right)}_3}}
\end{array}\\
8Fe\; + \;30HN{O_3}\; \to \;3N{H_4}N{O_3}\; + \;9{H_2}O\; + \;8Fe{\left( {N{O_3}} \right)_3}\\
\begin{array}{*{20}{l}}
{Cu}& + &{2{H_2}S{O_4}}& \to &{2{H_2}O}& + &{S{O_2}}& + &{CuS{O_4}}
\end{array}\\
6HN{O_3} + S \to 2{H_2}O + {H_2}S{O_4} + 6N{O_2}\\
4FeS + 7{O_2} \to 2F{e_2}{O_3} + 4S{O_2}\\
4Al + {\rm{3}}O2 \to {\rm{2}}A{l_2}{O_3}\\
3C{l_2} + 2N{H_3} \to 6HCl + {N_2}\\
3CuO + 2N{H_3} \to 3Cu + 3{H_2}O + {N_2}\\
\begin{array}{*{20}{l}}
{4HCl}& + &{Mn{O_2}}& \to &{C{l_2}}& + &{2{H_2}O}& + &{MnC{l_2}}
\end{array}\\
\begin{array}{*{20}{l}}
{3{H_2}S}& + &{2HN{O_3}}& \to &{4{H_2}O}& + &{2NO}& + &{2S}
\end{array}
\end{array}\)