Match the following :

LIST I	LIST II
(A) pH of unpolluted rain water	(I) ${\mathrm{H}}_2\mathrm{C}=\mathrm{CH}-\mathrm{CHO}$
(B) Acid rain	(II) $5.6$
(C)  Acrolein	(III) ${\mathrm{NO}}_2,{\mathrm{CO}}_2$
(D) Freon	(IV)  ${\mathrm{CF}}_2{\mathrm{Cl}}_2$
	(V)  ${\mathrm{CaOCl}}_2$

pH of unpolluted rainwater is slightly acidic which is around 5.6.

Acid rain is mainly due to presence of sulphur dioxide and carbon dioxide.

The structural formula of Acrolein is  

${\mathrm{H}}_2\mathrm{C}=\mathrm{CH}-\mathrm{CHO}$

The structural formula of Freon is ${\mathrm{CF}}_2{\mathrm{Cl}}_2$.