Question

Which of the following are coloured and paramagnetic both ?
$N{O}_2,C{u}^{+},O_2,O_3,H{g}_2^{2+},C{d}^{2+},Al,C\left(graphite\right)$

• A. $N{O}_2$
• B. $N{O}_2$ , $O_3$
• C. $H{g}_2^{2+}$
• D. $N{O}_2$, $C{u}^{+}$

Answer 1

The correct option is A $N{O}_2$

$N{O}_2$ contains 1 unpaired electron. Hence, it is colored and para magnetic. N atom has 5 valence electrons. Out of which it uses 2 valence electrons to form a sigma bond and a pi bond with O atom. N also uses 2 valence electrons to form a coordinate bond with another O atom. Thus 4 out of 5 valence electrons of N are involved in the bond formation. There is one unpaired electron left on nitrogen. Due to this nitrogen dioxide is para magnetic and brown colored gas.