Đáp án:
\(\begin{array}{l}
16,C\\
17,C\\
18,B\\
19,C\\
20,A
\end{array}\)
Giải thích các bước giải:
16,
\(2FeC{l_3} + Cu \to CuC{l_2} + 2FeC{l_2}\)
ta có: 2+1+1+2=6
17,
\(Zn + 2{H_2}S{O_4} \to ZnS{O_4} + S{O_2} + 2{H_2}O\)
18,
\(Mn{O_2} + 4HCl \to MnC{l_2} + C{l_2} + 2{H_2}O\)
19,
\(2KMn{O_4} + 16HCl \to 2KCl + 2MnC{l_2} + 5C{l_2} + 8{H_2}O\)
Ta có: 2+5=7
20,
\(4Zn + 5{H_2}S{O_4} \to 4ZnS{O_4} + {H_2}S + 4{H_2}O\)
