Question

$2N{O}_2\rightleftharpoons N_2{O}_4$ The dimerisation of $N{O}_2$ is accompainied with :

• A. decrease in paramagnetism
• B. change in color
• C. increase in temperature
• D. increase in paramagnetism

Answer 1

Answer: (A), (B)

The correct options are
A decrease in paramagnetism
B change in color

In the $N{O}_2$ molecule the nitrogen atom has a single unpaired electron. The molecule will tend to dimerise so that this unpaired electron can be paired with another to form the $N_2{O}_4$ molecule. $N{O}_2$ molecule is an odd electron molecule and hence paramagnetic. Due to possession of odd electron, it is coloured. Whereas its dimer $N_2{O}_4$ has no unpaired electron so it is colourless and less paramagnetic.