Đáp án:
\(\begin{array}{l}
15\,C\\
16\,C\\
17\,A\\
18\,B\\
19\,D\\
20\,B
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
16)\\
N{a_2}S + {H_2}S{O_4} \to N{a_2}S{O_4} + {H_2}S\\
C{H_3}COONa + HCl \to NaCl + C{H_3}COOH\\
AgN{O_3} + NaCl \to AgCl + NaN{O_3}\\
17)\\
BTDT:{n_{{H^ + }}} = {n_{C{l^ - }}} + 2{n_{S{O_4}^{2 - }}} = 0,72\,mol\\
19)\\
{H_2}S{O_4} + 2NaOH \to N{a_2}S{O_4} + 2{H_2}O\\
{H^ + } + O{H^ - } \to {H_2}O\\
20)\\
B{a^{2 + }} + S{O_4}^{2 - } \to BaS{O_4}
\end{array}\)
