Đáp án:
\(\begin{array}{l}
1 - e,c\\
2 - b\\
3 - c\\
4 - c,d,e,f
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
1,\\
CaO + {H_2}O \to Ca{(OH)_2}\\
K + {H_2}O \to KOH + \dfrac{1}{2}{H_2}\\
2,\\
BaC{l_2} + CuS{O_4} \to BaS{O_4} + CuC{l_2}\\
4,\\
CaO + {H_2}S{O_4} \to CaS{O_4} + {H_2}O\\
Ca{(OH)_2} + {H_2}S{O_4} \to CaS{O_4} + 2{H_2}O\\
2K + {H_2}S{O_4} \to {K_2}S{O_4} + {H_2}\\
2Al + 3{H_2}S{O_4} \to A{l_2}{(S{O_4})_3} + 3{H_2}
\end{array}\)