In the given reaction A will be `:`

Answer

1

Explanation

`{:(N_(2)O_(4)hArr,2NO_(2),,P+P=0.4atm,,P_(N_(2))=0.6atm),(P_(0),-,,K_(p)=(P^(2))/(P)=0.25,,),(P_(0)-P'//2=P,P,,P=4P^(2),,),(4P'^(2)+P'-0.4=0,,,P=0.18,,),(P'=0.22,,,,,):}`
Degree of dissociation `=(P'//2)/(P_(0))=(0.11)/(0.18+0.11)=0.38`