Why does NO2 react with HCl ? What is the mechanism of the reaction? [closed]








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I found the following reaction given in a certain book:
 $$\ce{2NO2 + 4HCl -> 2NOCl + Cl2 + H2O}$$


I cannot think of any reason why an acidic oxide like $\ce{NO2}$ will react with an acid like $\ce{HCl}$. 


So, why will they react? And, what will be the mechanism of the reaction?




Yes, it is a typical redox where nitrogen dioxide is an oxidising agent and hydrochloric is a mild reducing agent as Ivan noted.


The reaction proceed in two phases:


$$
\begin{align}
\ce{NO2 + 2HCl ->[\Delta] NO + Cl2 + H2O} & \tag{R1}\\
\end{align}
$$


Now some nitrogen monoxide react with water to form nitrosyl chloride.


$$
\begin{align}
\ce{Cl2 + 2NO -> 2NOCl} & \tag{R2}\\
\end{align}
$$


Finally, we get our main reaction


$$
\begin{align}
\ce{2NO2 + 4HCl -> 2NO + 2Cl2 + 2H2O} & \tag{R1\*2}\\
\ce{2NO2 + 4HCl -> (2NO + Cl2) + Cl2 + 2H2O}\\
\ce{2NO2 + 4HCl -> 2NOCl + 2H2O + Cl2} & \tag{R3}\\
\end{align}
$$


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