According to the explanation given in the previous session about Keq, we will follow the same step by step in order to find this Keq as well, starting by setting up the reaction:
2 NO2 <--> N2O4
We have:
0.4 L
0.35 moles of N2O4
0.26 moles of NO2
Finding the concentration of each compound:
M = 0.35/0.4
M = 0.875 for N2O4
M = 0.26/0.4
M = 0.65 for NO2
Now finding the Keq:
Keq = [0.875]/[0.65]^2
Keq = 2.1, letter C