AP EAPCET 20-Aug-2021 Shift 1 Paper

‌	N2O4(g)	⇌	2NO2(g)
Initially	1‌mol	‌	0‌mol
At‌equilibrium	(1−0.5)‌mol	‌	2×0.5‌mol

Total number of moles =0.5+1=1.5‌mol
pN2O4=

0.5

1.5

×1‌atm=

1

3

‌atm
pNO2=

1

1.5

×1‌atm=

2

3

‌atm
According [o law of chemical equilibrium
Kp=

p2NO2

pN2O4

=

( 2 3 )2

( 1 3 )

=1.33‌atm
We know,
ΔG°=−2.303‌RT‌log‌Kp
Substituting value in Eq. (i), we get
=−7.79 atm litre
1‌atm litre =101.32500 joules
−7.79 atm litre =−7.79×101.32 joules =−789.2J‌mol−1≈−790J‌mol−1