For the equilibrium
2NO2(g)⇌N2O4(g)Kc is 1.7 at 400 K and 0.30 at 500 K. A sealed flask is heated to 500 K and contains [NO2]=0.40M and [N2O4]=0.12M. Which option gives the value of Qc at 500 K and predicts how the system will shift to reach equilibrium at that temperature?
a) Qc=0.30; the system is already at equilibrium.
b) Qc=1.3; the reaction will form more NO2.
c) Qc=0.75; the reaction will form more NO2.
d) Qc=0.75; the reaction will form more N2O4.