`2NO_(2(g))` (brown) `hArr N_2O_(4(g)) , DeltaH`=57.2 kJ `mol^(-1)` if the reaction vessel kept in ice and hot water than what is the change in colour ?

Explanation

This reaction is exothermic. So at lower temperature the forward reaction take place. So in mixture `NO_2` decreases so brown colour. decreases. If the vessel kept in hot water then the reaction take place in reverse direction and concentration of `NO_2` increases so brown colour increases.