1)

Khi cho kẽm vào axit clohidric thì kẽm tan, tạo dung dịch không màu đồng thời sủi bọt khí không màu.

Phản ứng xảy ra:

\(Zn + 2HCl\xrightarrow{{}}ZnC{l_2} + {H_2}\)

2)

a)

\({n_{HCl}} = 0,8.1,2 = 0,96{\text{ mol}}\)

\( \to {m_{HCl}} = 0,96.36,5 = 35,04{\text{ gam}}\)

b)

\({m_{dd}} = {m_{muối}} + {m_{{H_2}O}} = 50 + 350 = 400{\text{ gam}}\)

\( \to C{\% _{muối}} = \frac{{50}}{{400}} = 12,5\% \)

3)

Phản ứng xảy ra:

\(2Al + 3{H_2}S{O_4}\xrightarrow{{}}A{l_2}{(S{O_4})_3} + 3{H_2}\)

Ta có:

\({n_{{H_2}}} = \frac{{6,72}}{{22,4}} = 0,3{\text{ mol}}\)

\( \to {n_{A{l_2}{{(S{O_4})}_3}}} = \frac{1}{3}{n_{{H_2}}} = \frac{1}{3}.0,3 = 0,1{\text{ mol}}\)

\( \to {m_{A{l_2}{{(S{O_4})}_3}}} = 0,1.(27.2 + 96.3) = 34,2{\text{ gam}}\)

\({n_{{H_2}S{O_4}}} = {n_{{H_2}S{O_4}}} = 0,3{\text{ mol}}\)

\( \to {m_{{H_2}S{O_4}}} = 0,3.98 = 29,4{\text{ gam}}\)

\( \to C{\% _{{H_2}S{O_4}}} = \frac{{{m_{{H_2}S{O_4}}}}}{{{m_{dd}}}} = \frac{{29,4}}{{200}} = 14,7\% \)