Why does `NO_(2)` dimerise ?

Why does NO_(2) irritate eyes and nose?

Why NO_2 dimerise to N_2O_4 ?

Give reasons for the following : (a) CN^(-) ion is known but CP^(-) ion is not known (b) NO_(2) dimerises to form N_(2)O_(4)

When temperature is lowered NO_2 dimerises . It is accompanised by :

Explain why NO_2 dimerises.

Why is NO_(2) paramagnetic in gaseous state but the solid obtained on cooling is diamagnetic?

Give reasons for the following: NO_2 dimerises.