LE CHATELIER'S PRINCIPLE: NO2 & N2O4 - TEMPERATURE (2 0f 3)<br />
Liquid NO2<br />
The equilibrium of N2O4(g)=2NO2(g) moves to the right when the test tube is warmed and the frozen NO2 melts to a liquid. The concentration of red-brown Nitrogen dioxide gas (NO2) increases and the color darkens.