Cho các phản ứng sau Khí E là chất nào sau đây H2

* Hướng dẫn giải

Đáp án D

$$\begin{gathered} E là H_2. PTHH: \\ \left(1\right) Mn{O}_2 + 4HCl \\ \to MnC{l}_2+\underset{B}{\underbrace{C{l}_2}} +2H_{2}O \\ \underset{B}{\left(2\right) \underbrace{C{l}_2}}+\underset{C}{\underbrace{2NaOH}} \\ \to \underset{Nước Gia-ven}{\underbrace{NaCl+NaClO+H_{2}O}} \\ \underset{C}{\left(3\right) \underbrace{NaOH}}+HCl \\ \to \underset{D}{\underbrace{NaCl}}+H_{2}O \\ \left(4\right) \underset{D}{\underbrace{2NaCl}}+ 2H_{2}O\underset{có mn}{\overset{Đp dd }{\to }}2NaOH + \underset{E}{\underbrace{H_2}}+\underset{B}{\underbrace{C{l}_2}} \end{gathered}$$