LIST - 1		LIST - 2
A)	N2O	i)	sp2 and planar triangle
B)	HNO2	ii)	Nitrite and nitro form
C)	${\mathrm{NO}}_3^{-}$	iii)	sp3 and tetrahedron
D)	HNO4	iv)	Laughing gas
		v)	Peroxy bond

	(A)	(B)	(C)	(D)
1)	i	ii	iii	iv
2)	iii	ii	iv	i
3)	ii	v	iii	iv
4)	iv	ii	i	v

Laughing gas is N₂O (nitrous oxide). Hence, A matches with iv.

Nitrous acid exists in two tautomeric forms
(1) nitro form as in nitro alkanes
(2) nitrite form as in alkyl nitrite

Hence, B matches with ii.

In ${\mathrm{NO}}_3^{-}$, N has sp² and molecule has planar triangle shape. Hence, C matches with i.

Structure of HNO4 is shown below which shows that there is one peroxy bond. Hence, D matches with v.