Em tham khảo nha :
\(\begin{array}{l}
a)\\
{n_{hh}} = \dfrac{{16,8}}{{22,4}} = 0,75mol\\
hh:C{H_4}(a\,mol);{C_2}{H_2}(b\,mol)\\
\left\{ \begin{array}{l}
a + b = 0,75\\
2a - b = 0
\end{array} \right.\\
\Rightarrow a = 0,25;b = 0,5\\
{C_2}{H_2} + 2B{r_2} \to {C_2}{H_2}B{r_4}\\
\dfrac{{0,5}}{1} > \dfrac{{0,8}}{2} \Rightarrow {C_2}{H_2}\text{ dư}\\
\text{Vậy dung dịch Brom mất màu}\\
b)\\
{n_{B{r_2}}} = 2{n_{{C_2}{H_2}}} = 1mol\\
{m_{B{r_2}}} = 1 \times 160 = 160g\\
{m_{{\rm{dd}}B{r_2}}} = \dfrac{{160 \times 100}}{{20}} = 800g
\end{array}\)
