Em tham khảo nha:

 \(\begin{array}{l}
4)\\
a)\\
2R + C{l_2} \to 2RCl\\
{n_{C{l_2}}} = \dfrac{{3,36}}{{22,4}} = 0,15\,mol\\
{n_R} = 2{n_{C{l_2}}} = 0,3\,mol\\
{M_R} = \dfrac{{6,9}}{{0,3}} = 23\,g/mol \Rightarrow R:Natri(Na)\\
b)\\
{n_{NaCl}} = {n_{Na}} = 0,3\,mol\\
NaCl + AgN{O_3} \to AgCl + NaN{O_3}\\
{n_{AgN{O_3}}} = \frac{{170 \times 20\% }}{{170}} = 0,2\,mol\\
\dfrac{{0,3}}{1} > \dfrac{{0,2}}{1} \Rightarrow NaCl \text{ dư}\\
{n_{AgCl}} = {n_{AgN{O_3}}} = 0,2\,mol\\
{m_{AgCl}} = 0,2 \times 143,5 = 28,7g\\
5)\\
2KMn{O_4} + 16HCl \to 2KCl + 2MnC{l_2} + 5C{l_2} + 8{H_2}O\\
{n_{C{l_2}}} = \dfrac{{2,24}}{{22,4}} = 0,1\,mol\\
{n_{KMn{O_4}}} = \dfrac{{0,1 \times 2}}{5} = 0,04\,mol\\
{m_{KMn{O_4}}} = 0,04 \times 158 = 6,32g
\end{array}\)